Session Index

Antibiotic resistance kills an estimated 700,000 people each year worldwide, and study predicts that this number could rise to 10 million by 2050 if efforts are not made to curtail resistance (Nature, 2017, 543:15). Yet, the pace of resistance acquisition from mutation in pathogens is faster than clinical introduction of new antibiotics. Confronted with this severe situation, health organizations are calling for alternative ways to combat the resistance. Through label-free chemical imaging of methicillin-resistant Staphylococcus aureus (MRSA), my group discovered that staphyloxanthin, an anti-oxidative carotenoid pigment residing inside the bacterium cell membrane, is prone to bleaching by blue light. We further found that photobleaching of staphyloxanthin sensitizes MRSA to low-concentration hydrogen peroxide. Using cultured S. aureus, we found this synergistic antimicrobial therapy surprisingly effective (over 2-log reduction compared to untreated). Based on this initial finding, we have maximized the efficacy of staphyloxanthin destruction through mechanistic studies and explore the potential of staphyloxanthin bleaching in eliminating MRSA in biofilms and macrophages. We elucidated changes to the bacterial membrane upon staphyloxanthin bleaching and sensitize MRSA to a broad spectrum of existing antibiotics. Notably, by exploiting the intrinsic chromophore produced by the bacteria, our method is fundamentally different from the well-developed photodynamic therapy that relies on administered agents.

 

Here we demonstrate the first noninvasive treatment assessment of solar lentigines with histopathological details. With the high contrast, noninvasiveness, high resolution, high penetration, and the quantification capability of harmonic generation microscopy, we quantified the following parameters: stratum corneum thickness, dermal papillae depth, basal cell height, and melanin mass density.

 

In order to obtain high-speed and clear 3D images, we built a two-photon excitation microscope and selected the field programmable gate array (FPGA) card to accurately control the tunable acoustic gradient (TAG) lens and resonant mirror for single-point scanning. With this system volume rate can reach 30 volumes per second.

 

We have successfully demonstrated a multiphoton microscopy system with a sub-micron resolution for imaging with a record-large field of view. A control software was further developed for acquiring, processing and displaying real time images with a record-high sampling rate.

 

A thin film transistor (TFT) biosensor with gold sensing electrode was demonstrated for biochemical reaction detection. Based on current signals and diffusion characteristics of different biomolecules, we were able to study reaction kinetics between bioreactants, lysozyme and tri-N-acetylglucosamine (tri-NAG) in this work, with rate constant being 1.976×10-4 (s-1).

 

Hyperspectral, a combination of spatial information and spectral information. We present a review of visible and near-infrared spectroscopy and imaging technique for biological tissue optical characterization. Studies indicate notable absorption features of hemoglobin in spectroscopy, therefore, we attempt to utilize those feature to detect diabetes.