@article{hetzler_marinakos_lott_mohammad_lass-napiorkowska_kolbe_turrentine_fields_overton_marie_et al._2024, title={Adeno-associated virus genome quantification with amplification-free CRISPR-Cas12a}, ISSN={["1476-5462"]}, DOI={10.1038/s41434-024-00449-x}, journal={GENE THERAPY}, author={Hetzler, Zach and Marinakos, Stella M. and Lott, Noah and Mohammad, Noor and Lass-Napiorkowska, Agnieszka and Kolbe, Jenna and Turrentine, Lauren and Fields, Delaney and Overton, Laurie and Marie, Helena and et al.}, year={2024}, month={Mar} }
 @article{jamalzadegan_kim_mohammad_koduri_hetzler_lee_dickey_wei_2024, title={Liquid Metal-Based Biosensors: Fundamentals and Applications}, volume={1}, ISSN={["1616-3028"]}, url={https://doi.org/10.1002/adfm.202308173}, DOI={10.1002/adfm.202308173}, abstractNote={Biosensors are analytical tools for monitoring various parameters related to living organisms, such as humans and plants. Liquid metals (LMs) have emerged as a promising new material for biosensing applications in recent years. LMs have attractive physical and chemical properties such as deformability, high thermal and electrical conductivity, low volatility, and low viscosity. LM‐based biosensors represent a new strategy in biosensing particularly for wearable and real‐time sensing. While early demonstrations of LM biosensors focus on monitoring physical parameters such as strain, motion, and temperature, recent examples show LM can be an excellent sensing material for biochemical and biomolecular detection as well. In this review, the recent progress of LM‐based biosensors for personalized healthcare and disease monitoring via both physical and biochemical signaling is survey. It is started with a brief introduction of the fundamentals of biosensors and LMs, followed by a discussion of different mechanisms by which LM can transduce biological or physiological signals. Next, it is reviewed example LM‐based biosensors that have been used in real biological systems, ranging from real‐time on‐skin physiological monitoring to target‐specific biochemical detection. Finally, the challenges and future directions of LM‐integrated biosensor platforms is discussed.}, journal={ADVANCED FUNCTIONAL MATERIALS}, author={Jamalzadegan, Sina and Kim, Sooyoung and Mohammad, Noor and Koduri, Harshita and Hetzler, Zach and Lee, Giwon and Dickey, Michael D. and Wei, Qingshan}, year={2024}, month={Jan} }
 @article{wang_sadeghi_velayati_paul_hetzler_danilov_ligler_wei_2023, title={Low-rate smartphone videoscopy for microsecond luminescence lifetime imaging with machine learning}, volume={2}, ISSN={["2752-6542"]}, url={https://doi.org/10.1093/pnasnexus/pgad313}, DOI={10.1093/pnasnexus/pgad313}, abstractNote={Abstract Time-resolved techniques have been widely used in time-gated and luminescence lifetime imaging. However, traditional time-resolved systems require expensive lab equipment such as high-speed excitation sources and detectors or complicated mechanical choppers to achieve high repetition rates. Here, we present a cost-effective and miniaturized smartphone lifetime imaging system integrated with a pulsed ultraviolet (UV) light-emitting diode (LED) for 2D luminescence lifetime imaging using a videoscopy-based virtual chopper (V-chopper) mechanism combined with machine learning. The V-chopper method generates a series of time-delayed images between excitation pulses and smartphone gating so that the luminescence lifetime can be measured at each pixel using a relatively low acquisition frame rate (e.g. 30 frames per second [fps]) without the need for excitation synchronization. Europium (Eu) complex dyes with different luminescent lifetimes ranging from microseconds to seconds were used to demonstrate and evaluate the principle of V-chopper on a 3D-printed smartphone microscopy platform. A convolutional neural network (CNN) model was developed to automatically distinguish the gated images in different decay cycles with an accuracy of >99.5%. The current smartphone V-chopper system can detect lifetime down to ∼75 µs utilizing the default phase shift between the smartphone video rate and excitation pulses and in principle can detect much shorter lifetimes by accurately programming the time delay. This V-chopper methodology has eliminated the need for the expensive and complicated instruments used in traditional time-resolved detection and can greatly expand the applications of time-resolved lifetime technologies.}, number={10}, journal={PNAS NEXUS}, author={Wang, Yan and Sadeghi, Sina and Velayati, Alireza and Paul, Rajesh and Hetzler, Zach and Danilov, Evgeny and Ligler, Frances S. and Wei, Qingshan}, editor={Reis, RuiEditor}, year={2023}, month={Sep} }
 @article{hetzler_lott_poonam_dalgan_wei_2023, title={Single-use biosensors for biomanufacturing: Perspective on the state-of-the-art}, volume={28}, ISSN={["2468-4511"]}, url={https://doi.org/10.1016/j.cobme.2023.100512}, DOI={10.1016/j.cobme.2023.100512}, journal={CURRENT OPINION IN BIOMEDICAL ENGINEERING}, author={Hetzler, Zach and Lott, Noah and Poonam, Aditi Dey and Dalgan, Selen and Wei, Qingshan}, year={2023}, month={Dec} }
 @article{mohammad_talton_hetzler_gongireddy_wei_2023, title={Unidirectional trans-cleaving behavior of CRISPR-Cas12a unlocks for an ultrasensitive assay using hybrid DNA reporters containing a 3' toehold}, volume={8}, ISSN={["1362-4962"]}, url={https://doi.org/10.1093/nar/gkad715}, DOI={10.1093/nar/gkad715}, abstractNote={Abstract CRISPR-Cas12a can induce nonspecific trans-cleavage of dsDNA substrate, including long and stable λ DNA. However, the mechanism behind this is still largely undetermined. In this study, we observed that while trans-activated Cas12a didn’t cleave blunt-end dsDNA within a short reaction time, it could degrade dsDNA reporters with a short overhang. More interestingly, we discovered that the location of the overhang also affected the susceptibility of dsDNA substrate to trans-activated Cas12a. Cas12a trans-cleaved 3′ overhang dsDNA substrates at least 3 times faster than 5′ overhang substrates. We attributed this unique preference of overhang location to the directional trans-cleavage behavior of Cas12a, which may be governed by RuvC and Nuc domains. Utilizing this new finding, we designed a new hybrid DNA reporter as nonoptical substrate for the CRISPR-Cas12a detection platform, which sensitively detected ssDNA targets at sub picomolar level. This study not only unfolded new insight into the trans-cleavage behavior of Cas12a but also demonstrated a sensitive CRISPR-Cas12a assay by using a hybrid dsDNA reporter molecule.}, journal={NUCLEIC ACIDS RESEARCH}, author={Mohammad, Noor and Talton, Logan and Hetzler, Zach and Gongireddy, Megha and Wei, Qingshan}, year={2023}, month={Aug} }
 @article{hetzler_wang_krafft_jamalzadegan_overton_kudenov_ligler_wei_2022, title={Flexible sensor patch for continuous carbon dioxide monitoring}, volume={10}, ISSN={["2296-2646"]}, DOI={10.3389/fchem.2022.983523}, abstractNote={Monitoring and measurement of carbon dioxide (CO2) is critical for many fields. The gold standard CO2 sensor, the Severinghaus electrode, has remained unchanged for decades. In recent years, many other CO2 sensor formats, such as detection based upon pH-sensitive dyes, have been demonstrated, opening the door for relatively simple optical detection schemes. However, a majority of these optochemical sensors require complex sensor preparation steps and are difficult to control and repeatably execute. Here, we report a facile CO2 sensor generation method that suffers from none of the typical fabrication issues. The method described here utilizes polydimethylsiloxane (PDMS) as the flexible sensor matrix and 1-hydroxypyrene-3,6,8-trisulfonate (HPTS), a pH-sensitive dye, as the sensing material. HPTS, a base (NaOH), and glycerol are loaded as dense droplets into a thin PDMS layer which is subsequently cured around the droplet. The fabrication process does not require prior knowledge in chemistry or device fabrication and can be completed as quickly as PDMS cures (∼2 h). We demonstrate the application of this thin-patch sensor for in-line CO2 quantification in cell culture media. To this end, we optimized the sensing composition and quantified CO2 in the range of 0–20 kPa. A standard curve was generated with high fidelity (R 2 = 0.998) along with an analytical resolution of 0.5 kPa (3.7 mm Hg). Additionally, the sensor is fully autoclavable for applications requiring sterility and has a long working lifetime. This flexible, simple-to-manufacture sensor has a myriad of potential applications and represents a new, straightforward means for optical carbon dioxide measurement. Graphical Abstract}, journal={FRONTIERS IN CHEMISTRY}, author={Hetzler, Zach and Wang, Yan and Krafft, Danny and Jamalzadegan, Sina and Overton, Laurie and Kudenov, Michael W. and Ligler, Frances S. and Wei, Qingshan}, year={2022}, month={Sep} }