@article{kadian_kumari_sahoo_shukla_narayan_2024, title={Machine learning enabled microneedle-based colorimetric pH sensing patch for wound health monitoring and meat spoilage detection}, volume={200}, ISSN={["1095-9149"]}, url={https://doi.org/10.1016/j.microc.2024.110350}, DOI={10.1016/j.microc.2024.110350}, abstractNote={Since pH can alter the biological functions, level of nutrients, wound healing process, and the behavior of chemicals, various healthcare and food industries are showing increased interest in manufacturing low-cost optical pH sensors for meat spoilage detection and wound health monitoring. To meet this demand, we have developed a simple and low-cost machine learning-enabled microneedle-based colorimetric pH sensing patch that can be used for food quality and wound health monitoring applications. The 3D–printed ultrasharp open side channel microneedle array facilitated the autonomous fluid extraction and transportation via surface tension for colorimetric pH sensing. Further, to predict the exact pH value against the obtained color on the pH-test strip, a machine learning model was prepared using experimentally collected different color images obtained from a known pH solution. Furthermore, to make the device user-friendly for older individuals and color-blind individuals, a simple and smartphone-enabled web application was prepared using the developed machine learning model. The proof-of-concept study of the developed patch was demonstrated by determining the pH of real meat samples before and after spoilage and detecting pH in two different skin-mimicking in vitro models (phantom gel and parafilm tape) using a smartphone. The analytical results demonstrated that the developed machine learning-enabled microneedle-based colorimetric pH sensing patch has excellent potential for wound health and food safety applications.}, journal={MICROCHEMICAL JOURNAL}, author={Kadian, Sachin and Kumari, Pratima and Sahoo, Siba Sundar and Shukla, Shubhangi and Narayan, Roger J.}, year={2024}, month={May} }
 @article{shukla_khanna_sahoo_joshi_narayan_2024, title={Nanomaterial-Coated Carbon-Fiber-Based Multicontact Array Sensors for In Vitro Monitoring of Serotonin Levels}, volume={7}, ISSN={["2576-6422"]}, url={http://dx.doi.org/10.1021/acsabm.3c01089}, DOI={10.1021/acsabm.3c01089}, abstractNote={In this study, we demonstrated the fabrication of multicontact hierarchical probes for the in vitro detection of serotonin levels. The basic three-dimensional (3D) bendable prototypes with 3 (C1), 6 (C2), or 9 (C3) contact surfaces were printed from polymeric resin via the digital light processing (DLP) technique. We chose ultrasonicated carbon fiber strands to transform these designs into multicontact carbon fiber electrodes (MCCFEs). The exposed carbon fiber (CF) surfaces were modified with aminopropyl alkoxysilane (APTMS), followed by the subsequent loading of palladium nanoclusters (PdNPs) to build active recording sites. CF functionalization with PdNPs was achieved by the wet chemical reduction of Pd(II) to Pd(0). The MCCFE configurations demonstrated an enhancement in the electroactive surface area and an improved voltammetric response toward 5-HT oxidation by increasing the points of the contacts (i.e., from C1 to C3). These MCCFEs are comparable to 3D-protruding electrodes as they can enable multipoint analyte detection. Along with the electrode patterns, morphological irregularities associated with both Pd-doped and undoped CFs supported the creation of proximal diffusion layers for facile mass transfer. Low detection limits of 0.8-10 nM over a wide concentration range, from 0.005 nM to 1 mM, were demonstrated. The MCCFE sensors had a relatively low standard deviation value of ∼2%. This type of sensitive and cost-effective electrochemical sensor may prove useful for collecting electrical impulses and long-term monitoring of 5-HT in vivo in addition to in vitro testing.}, number={1}, journal={ACS APPLIED BIO MATERIALS}, author={Shukla, Shubhangi and Khanna, Sumeer and Sahoo, Siba and Joshi, Naveen and Narayan, Roger}, year={2024}, month={Jan}, pages={472–484} }
 @article{joshi_shukla_khosla_vanderwal_stafslien_narayan_narayan_2024, title={Q-carbon as an emergent surface coating material for antimicrobial applications}, volume={791}, ISSN={["1879-2731"]}, url={https://doi.org/10.1016/j.tsf.2024.140227}, DOI={10.1016/j.tsf.2024.140227}, abstractNote={Q-carbon, an allotrope of carbon, exhibits exciting functional properties and robust mechanical strength. We propose that the surface of the Q-carbon can be functionalized by doping it with silicon to enhance its performance as a potential implant material. As such, a coating of silicon-doped Q-carbon (Si-Q-carbon) is shown to minimize the formation of biofilm, thus reducing the risk of microbial infection. We report the formation of Si-Q-carbon coatings of varied thicknesses (10nm and 20nm) through the plasma-enhanced chemical vapor deposition technique. The surface composition and the bonding characteristics of the thin films were evaluated by Raman spectroscopy, XPS, and EELS studies, which showed that the thinnest sample (10nm) has a high sp3 content of ∼85%. Furthermore, wettability and surface energy calculations were undertaken to investigate the surface characteristics of the coatings. The 10nm sample was found to be more hydrophilic with a water contact angle of 75.3° (± 0.6°). The antibacterial activity of Si-Q-carbon coatings was investigated using a Staphylococcus epidermidis agar plating technique, and the adhesion of bacteria was explained in terms of the surface properties of the thin films. We demonstrate that the Si-Q-carbon coating with the highest sp3 content is hydrophilic and showed a 57% reduction in adhered biofilm relative to a glass control. We envisage the potential application of Q-carbon in arthroplasty devices with enhanced mechanical strength and resistance to periprosthetic joint infections.}, journal={THIN SOLID FILMS}, author={Joshi, Naveen and Shukla, Shubhangi and Khosla, Nayna and Vanderwal, Lyndsi and Stafslien, Shane and Narayan, Jagdish and Narayan, Roger J.}, year={2024}, month={Feb} }
 @misc{shukla_jakowski_kadian_narayan_2023, title={Computational approaches to delivery of anticancer drugs with multidimensional nanomaterials}, volume={21}, ISSN={["2001-0370"]}, DOI={10.1016/j.csbj.2023.08.010}, abstractNote={Functionalized nanotubes (NTs), nanosheets, nanorods, and porous organometallic scaffolds are potential in vivo carriers for cancer therapeutics. Precise delivery through these agents depends on factors like hydrophobicity, payload capacity, bulk/surface adsorption, orientation of molecules inside the host matrix, bonding, and nonbonding interactions. Herein, we summarize advances in simulation techniques, which are extremely valuable in initial geometry optimization and evaluation of the loading and unloading behavior of encapsulated drug molecules. Computational methods broadly involve the use of quantum and classical mechanics for studying the behavior of molecular properties. Combining theoretical processes with experimental techniques, such as X-ray crystallography, NMR spectroscopy, and bioassays, can provide a more comprehensive understanding of the structure and function of biological molecules. This integrated approach has led to numerous breakthroughs in drug discovery, enzyme design, and the study of complex biological processes. This short review provides an overview of results and challenges described from erstwhile investigations on the molecular interaction of anticancer drugs with nanocarriers of different aspect ratios.}, journal={COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL}, author={Shukla, Shubhangi and Jakowski, Jacek and Kadian, Sachin and Narayan, Roger J.}, year={2023}, pages={4149–4158} }
 @article{machekposhti_khanna_shukla_narayan_2023, title={Microneedle fabrication methods and applications}, ISSN={["2159-6867"]}, DOI={10.1557/s43579-023-00355-0}, abstractNote={Microneedles are microscale needle-shaped devices that have attracted attention from the biomedical engineering community for transdermal drug delivery, sensing, and vaccine delivery. These devices do not inflict significant discomfort during skin penetration. Microneedles have recently been used to detect physiologically relevant molecules in interstitial fluid for health monitoring. In this review, technical challenges associated with microneedle processing are considered. The mechanical requirements associated with microneedle penetration of the skin are described. The use of polymers, bioceramics, and natural materials in microneedle fabrication is described. Recent uses of microneedles in biosensing, drug delivery, and vaccine delivery are described. Graphical abstract}, journal={MRS COMMUNICATIONS}, author={Machekposhti, Sina Azizi and Khanna, Sumeer and Shukla, Shubhangi and Narayan, Roger}, year={2023}, month={Mar} }
 @article{shukla_machekposhti_joshi_joshi_narayan_2023, title={Microneedle-Integrated Device for Transdermal Sampling and Analyses of Targeted Biomarkers}, volume={4}, ISSN={["2688-4046"]}, url={http://dx.doi.org/10.1002/smsc.202200087}, DOI={10.1002/smsc.202200087}, abstractNote={Currently available point‐of‐care systems for body fluid collection exhibit poor integration with sensors. Herein, the design of a disposable device for interstitial fluid (ISF) extraction as well as glucose, lactate, and potassium ion (K+) monitoring is reported on. It is minimally invasive and appropriate for single use, minimizing the risk of infection to the user. This microscale device contains a 3D‐printed cap‐like structure with a four‐by‐four microneedle (MN) array, bioreceptor‐modified carbon fiber (CF)‐sensing surface, and negative pressure convection technology. These features are incorporated within a compact, self‐contained, and manually operated microscale device, which is capable of withdrawing ≈3.0 μL of ISF from the skin. MN arrays applied with an upward driving force may increase the ISF flow rate. Moreover, functionalized CF working electrodes (WE1, WE2, WE3) are shown to selectively detect lactate, glucose, and K+ with high sensitivities of 0.258, 0.549, and 0.657 μA μm−1 cm−2 and low detection limits of 0.01, 0.080, 0.05 μm, respectively. Ex vivo testing on porcine skin is used to detect the ISF levels of the biomarkers. The microscale device can be a replacement for current point‐of‐care diagnostic approaches.}, number={6}, journal={SMALL SCIENCE}, publisher={Wiley}, author={Shukla, Shubhangi and Machekposhti, Sina Azizi and Joshi, Naveen and Joshi, Pratik and Narayan, Roger J.}, year={2023}, month={Apr} }
 @misc{kadian_shukla_narayan_2023, title={Probes for noninvasive biological visualization and biosensing of cancer cells}, volume={10}, ISSN={["1931-9401"]}, url={https://doi.org/10.1063/5.0166740}, DOI={10.1063/5.0166740}, abstractNote={The early detection of tumors and precancerous conditions is vital for cancer diagnosis. Advances in fluorescence microscopic techniques and materials synthesis processes have revolutionized biomarker detection and image-guided cancer surveillance. In particular, novel materials-based diagnostic tools and innovative therapies have facilitated a precise understanding of biological processes at the molecular level. This critical review presents an overview of bioimaging probes, including functionalized chromophoric systems, non-functionalized chromophoric systems, and nanoscale biosensors. Technical challenges and future directions related to these approaches are considered.}, number={4}, journal={APPLIED PHYSICS REVIEWS}, author={Kadian, Sachin and Shukla, Shubhangi and Narayan, Roger J.}, year={2023}, month={Dec} }
 @article{kadian_kumari_shukla_narayan_2023, title={Recent advancements in machine learning enabled portable and wearable biosensors}, volume={8}, ISSN={["2666-8319"]}, DOI={10.1016/j.talo.2023.100267}, abstractNote={Recent advances in noninvasive portable and wearable biosensors have attracted significant attention due to their capability to offer continual physiological information for continuous healthcare monitoring through the collection of biological signals. To make the collected biological data understandable and improve the efficacy of these biosensors, scientists have integrated machine learning (ML) with biosensors to analyze large sensing data through various ML algorithms. In this article, we have highlighted the recent developments in ML-enabled noninvasive biosensors. Initially, we introduced and discussed the basic features of ML algorithms used in data processing to build an intelligent biosensor system and the capability to make clinical decisions. Next, the principles of portable and wearable biosensors, the application of different ML models in diverse biosensors for healthcare applications, and their impact on the performance of biosensors are discussed. The last section highlights the challenges (such as data privacy, consistency, stability, accuracy, scalable production, and adaptive learning capacity), future prospects, and necessary steps required to address these issues, spotlighting their revolutionizing impact on the healthcare industry for the development of next-generation ML-enabled efficient biosensors.}, journal={TALANTA OPEN}, author={Kadian, Sachin and Kumari, Pratima and Shukla, Shubhangi and Narayan, Roger}, year={2023}, month={Dec} }
 @article{joshi_shukla_gupta_joshi_narayan_narayan_2023, title={Synthesis of laser-patterned MoS2 nanoneedles for advanced electrochemical sensing}, volume={6}, ISSN={["2159-6867"]}, url={http://dx.doi.org/10.1557/s43579-023-00381-y}, DOI={10.1557/s43579-023-00381-y}, abstractNote={We describe a novel excimer laser-based route for the fabrication of crystalline MoS2 nanoneedles. Laser annealing of MoS2 thin films at a low energy density of 0.08 Jcm−2 resulted in a closed-pack structure with low defects and excellent conductivity due to melting and rapid quenching. A further increase in laser annealing energy density resulted in the formation of MoS2 nano-needles. This structure of MoS2 was found to have a remarkable reduction ability for H2O2 at − 0.14 V over a wide linear range; a low detection limit (0.45 nM (S/N = 3)) and sensitivity of 2.38 μA/mM cm−2 were demonstrated.}, number={4}, journal={MRS COMMUNICATIONS}, publisher={Springer Science and Business Media LLC}, author={Joshi, Pratik and Shukla, Shubhangi and Gupta, Siddharth and Joshi, Naveen and Narayan, Jagdish and Narayan, Roger}, year={2023}, month={Jun} }
 @article{joshi_shukla_gupta_riley_narayan_narayan_2022, title={Excimer Laser Patterned Holey Graphene Oxide Films for Nonenzymatic Electrochemical Sensing}, volume={14}, ISSN={["1944-8252"]}, url={https://doi.org/10.1021/acsami.2c09096}, DOI={10.1021/acsami.2c09096}, abstractNote={The existence of point defects, holes, and corrugations (macroscopic defects) induces high catalytic potential in graphene and its derivatives. We report a systematic approach for microscopic and macroscopic defect density optimization in excimer laser-induced reduced graphene oxide by varying the laser energy density and pulse number to achieve a record detection limit of 7.15 nM for peroxide sensing. A quantitative estimation of point defect densities was obtained using Raman spectroscopy and confirmed with electrochemical sensing measurements. Laser annealing (LA) at 0.6 J cm-2 led to the formation of highly reduced graphene oxide (GO) by liquid-phase regrowth of molten carbon with the presence of dangling bonds, making it catalytically active. Hall-effect measurements yielded a mobility of ∼200 cm2 V-1 s-1. An additional increase in the number of pulses at 0.6 J cm-2 resulted in deoxygenation through the solid-state route, leading to the formation of holey graphene structure. The average hole size showed a hierarchical increase, with the number of pulses characterized with multiple microscopy techniques, including scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The exposure of edge sites due to high hole density after 10 pulses supported the formation of proximal diffusion layers, which led to facile mass transfer and improvement in the detection limit from 25.4 mM to 7.15 nM for peroxide sensing. However, LA at 1 J cm-2 with 1 pulse resulted in a high melt lifetime of molten carbon and the formation of GO characterized by a high resistivity of 3 × 10-2 Ω-cm, which was not ideal for sensing applications. The rapid thermal annealing technique using a batch furnace to generate holey graphene results in structure with uneven hole sizes. However, holey graphene formation using the LA technique is scalable with better control over hole size and density. This study will pave the path for cost-efficient and high-performance holey graphene sensors for advanced sensing applications.}, number={32}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Joshi, Pratik and Shukla, Shubhangi and Gupta, Siddharth and Riley, Parand R. and Narayan, Jagdish and Narayan, Roger}, year={2022}, month={Aug}, pages={37149–37160} }
 @article{joshi_riley_denning_shukla_khosla_narayan_narayan_2022, title={Laser-patterned carbon coatings on flexible and optically transparent plastic substrates for advanced biomedical sensing and implant applications}, volume={1}, ISSN={["2050-7534"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85125716163&partnerID=MN8TOARS}, DOI={10.1039/d1tc05176h}, abstractNote={Plasma and laser-based processing for tailoring DLC thin film properties for state-of-the-art wearable sensing applications.}, number={8}, journal={JOURNAL OF MATERIALS CHEMISTRY C}, publisher={Royal Society of Chemistry (RSC)}, author={Joshi, Pratik and Riley, Parand R. and Denning, Warren and Shukla, Shubhangi and Khosla, Nayna and Narayan, Jagdish and Narayan, Roger}, year={2022}, month={Jan} }
 @article{shukla_joshi_riley_narayan_2022, title={Square wave voltammetric approach to leptin immunosensing and optimization of driving parameters with chemometrics}, volume={216}, ISSN={["1873-4235"]}, DOI={10.1016/j.bios.2022.114592}, abstractNote={Square wave voltammetry serves as an effective analytical means to evaluate antigen-antibody coupling at the solid-liquid interface. Herein, we describe 3-aminopropyltrimethoxysilane (APTMS) induced irreversible immobilization of anti-leptin to micellar gold nanoparticles (AuNPs). Antibodies (Abs) were orthogonally loaded on micellized AuNP assemblies via amino residual groups. The ratio of bound Ab molecules was determined by the Bradford assay. The AuNP/Ab layer modified electrodes with variable antibody surface coverage (∼400 ± 55–200 ± 30 Ab/NP) were analyzed in terms of change in backward, net current (Ip) components. The rate of antigen coupling was found to be consistent with the variation in antibody density as well as the binding affinity. The lowest detection limit was observed at the femtomolar level (0.25 fM/mL) over a wide range of antigen concentration (6.2 ng/mL to 0.12 fg/mL). The variables affecting the epitope-paratope interaction were further optimized using a chemometric approach and a response surface methodology (RSM).}, journal={BIOSENSORS & BIOELECTRONICS}, author={Shukla, Shubhangi and Joshi, Pratik and Riley, Parand and Narayan, Roger J.}, year={2022}, month={Nov} }
 @article{shukla_huston_cox_satoskar_narayan_2022, title={Transdermal delivery via medical device technologies}, ISSN={["1744-7593"]}, DOI={10.1080/17425247.2022.2135503}, abstractNote={ABSTRACT Introduction Despite their effectiveness and indispensability, many drugs are poorly solvated in aqueous solutions. Over recent decades, the need for targeted drug delivery has led to the development of pharmaceutical formulations with enhanced lipid solubility to improve their delivery properties. Therefore, a dependable approach for administering lipid-soluble drugs needs to be developed. Areas covered The advent of 3D printing or additive manufacturing (AM) has revolutionized the development of medical devices, which can effectively enable the delivery of lipophilic drugs to the targeted tissues. This review focuses on the use of microneedles and iontophoresis for transdermal drug delivery. Microneedle arrays, inkjet printing, and fused deposition modeling have emerged as valuable approaches for delivering several classes of drugs. In addition, iontophoresis has been successfully employed for the effective delivery of macromolecular drugs. Expert opinion Microneedle arrays, inkjet printing, and fused deposition are potentially useful for many drug delivery applications; however, the clinical and commercial adoption rates of these technologies are relatively low. Additional efforts is needed to enable the pharmaceutical community to fully realize the benefits of these technologies.}, journal={EXPERT OPINION ON DRUG DELIVERY}, author={Shukla, Shubhangi and Huston, Ryan H. and Cox, Blake D. and Satoskar, Abhay R. and Narayan, Roger J.}, year={2022}, month={Oct} }