@article{he_lou_woody_he_2019, title={Amplification-by-Polymerization in Biosensing for Human Genomic DNA Detection}, volume={4}, ISSN={["2379-3694"]}, DOI={10.1021/acssensors.9b00133}, abstractNote={A polymerization reaction was employed as a signal amplification method to realize direct visualization of gender-specific DNA extracted from human blood in a polymerase chain reaction (PCR)-free fashion. Clear distinction between X and Y chromosomes was observed by naked eyes for detector-free sensing purposes. The grown polymer films atop X and Y chromosomes were quantitatively measured by ellipsometry for thickness readings. Detection assays have been optimized for genomic DNA recognition to a maximum extent by varying the selection of the proper blocking reagents, the annealing temperature, and the annealing time. Traditional PCR and gel electrophoresis for amplicon identification were conducted in parallel for performance comparison. In the blind test for blood samples examined by the new approach, 25 out of 26 were correct and one was false negative, which was comparable to, if not better than, the PCR results. This is the first time our amplification-by-polymerization technique is being used for chromosome DNA analysis. The potential of adopting the described sensing technique without PCR was demonstrated, which could further promote the development of a portable, PCR-free DNA sensing device for point-of-need applications.}, number={4}, journal={ACS SENSORS}, author={He, Peng and Lou, Xinhui and Woody, Susan M. and He, Lin}, year={2019}, month={Apr}, pages={992–1000} }
 @article{lou_he_2008, title={Surface passivation using oligo(ethylene glycol) in ATRP-assisted DNA detection}, volume={129}, ISSN={["0925-4005"]}, DOI={10.1016/j.snb.2007.07.130}, abstractNote={We recently reported a DNA sensing method using polymerization to amplify signal outputs [X. Lou, M.S. Lewis, C.B. Gorman, L. He, Anal. Chem. 77 (2005) 4698–4705]. In the current report an optimization of sensor surface chemistry is conducted in which (S–CH2CH2–OEG6–OMe)2 is used as the preferred surface passivation agent to reduce nonspecific adsorption experienced during ATRP-assisted DNA detection. The presence of oligo(ethylene glycol) (OEG) moieties on the sensor surface significantly reduces background adsorption of proteins, polymers, and reaction monomers used during DNA detection. The level of reduction in background nonspecific adsorption closely depends on the incubation solvent and the incubation time used, as evidenced by the ellipsometric and surface plasmon resonance (SPR) results. Reflectance FTIR results suggest that the surfaces with moderately ordered SAMs exhibit better protein resistance, consistent to the previous observations. Subsequent DNA binding experiments show no apparent decrease in DNA hybridization and ligation efficiencies when OEGylated self-assembled monolayers are used as the passivation layer. Improved DNA detection sensitivity is achieved from reduced background noises.}, number={1}, journal={SENSORS AND ACTUATORS B-CHEMICAL}, author={Lou, Xinhui and He, Lin}, year={2008}, month={Jan}, pages={225–230} }
 @article{lou_wang_he_2007, title={Core-shell Au nanoparticle formation with DNA-polymer hybrid coatings using aqueous ATRP}, volume={8}, ISSN={["1525-7797"]}, DOI={10.1021/bm061217+}, abstractNote={We report here a direct surface-grafting approach to forming DNA-containing polymer shells outside of Au nanoparticles using aqueous atom transfer radical polymerization (ATRP). In this approach, DNA molecules were immobilized on Au particles to introduce ATRP initiators on the surface. The same DNA molecules also acted as particle stabilizers through electrostatic repulsion and allowed particles to stay suspended in water. The immobilized ATRP initiators prompted polymer chain growth under certain conditions to form thick polymer shells outside of the particles. The formation of DNA-polymer hybrids outside of Au nanoparticles was characterized using absorption spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and gel electrophoresis. The presence of thick polymer shells improved particle stability in high ionic strength media, whereas particles with the DNA coating only aggregated. A visible color difference between these two particle solutions was clearly observed, providing the basis for DNA sensing in homogeneous solutions.}, number={5}, journal={BIOMACROMOLECULES}, author={Lou, Xinhui and Wang, Cuiying and He, Lin}, year={2007}, month={May}, pages={1385–1390} }
 @article{zheng_ballard_zheng_gao_ko_yang_brandt_lou_tai_lu_et al._2007, title={Design, synthesis, and evaluation of efflux substrate-metal chelator conjugates as potential antimicrobial agents}, volume={17}, ISSN={["1464-3405"]}, DOI={10.1016/j.bmcl.2006.10.094}, abstractNote={Maintaining a proper balance of metal concentrations is critical to the survival of bacteria. We have designed and synthesized a series of conjugates of metal chelators and efflux transporter substrates aimed at disrupting bacterial metal homeostasis to achieve bacterial killing. Biological studies showed that two of the compounds had very significant antimicrobial effect with an MIC value of 7.8 μg/mL against Gram-positive Bacillus subtilis.}, number={3}, journal={BIOORGANIC & MEDICINAL CHEMISTRY LETTERS}, author={Zheng, Yanling and Ballard, C. Eric and Zheng, Shi-Long and Gao, Xingming and Ko, Ko-Chun and Yang, Hsiuchin and Brandt, Gary and Lou, Xinhui and Tai, Phang C. and Lu, Chung-Dar and et al.}, year={2007}, month={Feb}, pages={707–711} }
 @article{lou_he_2006, title={DNA-accelerated atom transfer radical polymerization on a gold surface}, volume={22}, ISSN={["0743-7463"]}, DOI={10.1021/la052654x}, abstractNote={A significantly increased polymer growth rate was observed during a surface-initiated ATRP reaction in the presence of DNA molecules. To investigate this phenomenon, thiolated single-stranded DNA molecules (ssDNAs) with ATRP initiators coupled at the distal point were used as the model molecule in the study. In comparison, a small molecule, HS-(CH(2))(11)NHCOC(CH(3))(2)Br, was used to provide a less-polar surface coating for polymer grafting. 2-Hydroxyethyl methacrylate (HEMA) and monomethoxy-capped oligo(ethylene glycol) methacrylate (OEGMA) were used as the ATRP monomers. The polymer growth rates were monitored by measuring the thickness of the polymer films formed at different times. Our results show that the presence of DNA molecules, although at a less-than-1% surface coverage, significantly accelerated the growth rates of both poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(oligoethylene glycol methacrylate) (POEGMA) at the beginning of the ATRP reactions. This accelerating effect was suspected to be a combined result of the highly charged sugar-phosphate backbones of DNA molecules and the formation of Cu complexes with DNA bases. After the initial polymer growth, a smaller yet constant polymer growth rate was observed, suggesting the reduced influence of DNA molecules as the ATRP reaction centers moved farther away from the surface. Similar to conventional ATRP reactions, the polymer growth from surface-anchored DNA molecules was found to be strongly dependent on the composition and the concentration of the catalysts used. Specifically, a catalyst mixture of CuCl/30% CuBr(2)/bpy with 23 mM CuCl was found to provide the optimal reaction condition to yield the fastest polymer film growth among the conditions tested.}, number={6}, journal={LANGMUIR}, author={Lou, XH and He, L}, year={2006}, month={Mar}, pages={2640–2646} }
 @misc{lou_he_okelo_he_2006, title={Radical polymerization in biosensing}, volume={386}, ISSN={["1618-2642"]}, DOI={10.1007/s00216-006-0576-1}, abstractNote={This review briefly summarizes recently published work on radical polymerization in biosensor-related applications. Advancements in surface modification aimed at improving sensor biocompatibility and reducing nonspecific background noises are discussed. Direct applications of polymers as one of the key sensing elements in which they are used either as detection probes for the biomolecular binding events or as signal transducers to amplify sensing signals are detailed. Initial applications of radical polymerization reactions in biosensing are evident and appear promising.}, number={3}, journal={ANALYTICAL AND BIOANALYTICAL CHEMISTRY}, author={Lou, Xinhui and He, Peng and Okelo, Geoffrey O. and He, Lin}, year={2006}, month={Oct}, pages={525–531} }
 @article{lou_lewis_gorman_he_2005, title={Detection of DNA point mutation by atom transfer radical polymerization}, volume={77}, ISSN={["1520-6882"]}, DOI={10.1021/ac050706h}, abstractNote={We report here a new DNA detection method in which polymer growth in atom transfer radical polymerization (ATRP) is used as a means to amplify detection signals. In this method, DNA hybridization and ligation reactions led to the attachment of ATRP initiators on a solid surface where specific DNA sequences were located. These initiators subsequently triggered the growth of poly(hydroxyethyl methacrylate) (PHEMA) at the end of immobilized DNA molecules and formed polymer brushes. The formation of PHEMA altered substrate opacity, rendering the corresponding spots readily distinguishable to the naked eye. A second ATRP reaction to form branched polymers on the surface drastically improved the visibility of DNA hybridization and significantly shortened the detection time. The resulting polymer film was characterized using infrared spectroscopy, ellipsometry, contact angle measurements, and atomic force microscopy. Direct visualization of 1 fmol of target DNA molecules of interest was demonstrated. A proof-of-principle experiment to detect DNA point mutation was conducted. The perfectly matched DNA targets were distinctively differentiated from those with mutations. The demonstrated capability to detect DNA mutation with direct visualization laid the groundwork for the future development of detector-free testing kits in single-nucleotide polymorphism screenings.}, number={15}, journal={ANALYTICAL CHEMISTRY}, author={Lou, XH and Lewis, MS and Gorman, CB and He, L}, year={2005}, month={Aug}, pages={4698–4705} }
 @article{finkel_lou_wang_he_2004, title={Barcoding the microworld}, volume={76}, number={19}, journal={Analytical Chemistry}, author={Finkel, N. H. and Lou, X. H. and Wang, C. Y. and He, L.}, year={2004}, pages={353A–359} }