This conference presentation was prepared for the Photonic Diagnosis, Monitoring, Prevention, and Treatment of Infections and Inflammatory Diseases 2023 conference at SPIE BiOS, SPIE Photonics West 2023.

There is a need for fast methods of enumeration, identification, and viability evaluation of bacteria in diverse environments. Using multiphoton microscopy, NAD(P)H and FAD autofluorescence intensities and lifetimes have been widely used to study metabolism in a variety of biological specimens, but have traditionally been limited by slow acquisition. Recent work has developed technology to enable faster (~1 Hz) multiphoton fluorescence intensity and lifetime imaging with photon counting resolution with capabilities for dual-channel simultaneous NAD(P)H and FAD autofluorescence imaging. This enables label-free imaging of bacteria in native environments such as on skin and imaging of fast time-lapse responses to antibiotics.

Effective and early cancer and infection diagnosis, as well as personalized therapy, necessitate new methods of differential diagnosis and represent an outstanding medical task. Within this contribution we will highlight our recent efforts in translating spectroscopic approaches with focus on Raman spectroscopy towards routine clinical applications. In the first part of this contribution, a series of innovative multi-contrast marker free spectroscopy approaches (both microscopy and endoscopy based) for a precise intraoperative tumor margin control and reliable tumor classification to initiate an individualized therapy plan as quickly as possible. The second part highlights our most recent efforts to use Raman spectroscopy for diagnosing infectious diseases. These efforts include (I) predicting the immune response based on the patient's health, (II) quickly identifying the infection-causing pathogen and, in the case of bacterial infections, its resistance pattern; and (III) assessing the patient's response to treatment. An essential, often neglected point in the research of novel diagnostic methods is the sample preparation. Therefore, promising techniques based on particles and chips focusing on the enrichment of bacteria will be presented. The introduced approaches comprise the entire process chain i.e. from sampling to the final diagnostic result, and have a high potential to significantly reduce the critical parameter ‘time’ to initiate a personalized lifesaving therapy as compared to the gold standard microbiology. Novel, multi-user infrastructures are needed to bring these recent advances to patients faster. The Leibniz Centre for Photonics in Infection Research developing market-ready light-based diagnostic devices and novel infectious disease treatments is introduced.

This study aims to understand the application of thermal imaging to detect inflammatory bowel disease. Active inflammation increases tissue temperature, dissipating through different tissue types and fecal matter. In this study, heat conduction in swine gastrointestinal tissue were investigated experimentally and matched to theoretical models to measure the tissue's thermal properties and compute the depth at which inflammation that can be diagnosed by thermography. First, we measured the tissue's thermal conductivity, density, and heat capacitance using thermal transient heat conduction analysis through biomaterials. Then, using thermal conductivity and steady-state analysis of heat diffusion, we estimated the temperature drop through different types of swine intestinal tissue to calculate the detection depth range of thermography. The temperature drop through these experiments shows that heat rise from inflammation in the bowel should be detectable with infrared endoscopy.

This conference presentation was prepared for the Photonic Diagnosis, Monitoring, Prevention, and Treatment of Infections and Inflammatory Diseases 2023 conference at SPIE BiOS, SPIE Photonics West 2023.

Increasing antimicrobial resistance in bacterial pathogens has prompted a renewed interest in alternative approaches, such as bacteriophages (viruses that infect bacteria). However, phage therapy, as traditionally envisioned, suffers from several technical as well as safety challenges. We are developing a platform for controlled phage therapy using engineered filamentous phages coupled with plasmonic nanorods. Studies in our group have validated the safety and efficacy of this approach in vitro and in vivo.

Although immunotherapy, including immune checkpoint inhibitors, has revolutionized cancer treatment, only a small percentage of patients show sustained response. Recently, we have shown that photobiomodulation (PBM) with near-infrared (NIR) light in the NIR-II window reduces oxidative stress and supports CD8+ T cell proliferation, suggesting that PBM with NIR-II light may enhance anticancer immunity. In this study, we report a novel approach to support tumor-infiltrating CD8+ T cells by PBM using NIR-II laser with high tissue penetration depth. Lasers are a safe and low-cost therapy that can be used in combination with a broad range of other therapies without modification.

Otitis media (OM) is a common middle ear disease that is treated with antibiotics. However, over-prescription of antibiotics heightens the risk of antibiotic resistance. Here, we report the development and testing of a new cold microplasma (CMP) device to treat OM, and demonstrate the translation for in vivo use in a chinchilla animal model. In vitro nontypeable Haemophilus influenzae bacterial and biofilm samples and ex vivo tissue specimens were evaluated for inactivation and injury. CMP-induced effects on any infectious symptoms (middle ear fluid, biofilms) were longitudinally observed with OCT. This represents the first application of CMP treatments for OM therapy.

Antimicrobial resistance is significant concern to public health that negatively impacts the worldwide populace. With the increasing incidences of multidrug-resistant (MDR) pathogens, treatment of infections is becoming more difficult than ever before. In recent years, our team has been involved with the use of blue light (BL) for the treatment of infection. BL is a potent microbicide that can kill a multiplicity of pathogenic microbes. A concern, however, is that the effects of BL are short lived, when the light switches off, so do the antimicrobial effects.Therefore, we considered, that we could increase the longevity of microbicidal activity of BL via its concomitant application with antibiotics. In this study, we tested our hypothesis that aBL can enhance antibiotic activity in MDR bacteria.

This study investigated the aBL effects on bacterial species carrying β-lactamase genes and alterations in β-lactamase activity following aBL. In addition, we assessed the β-lactamase and protein damage induced by aBL and the bactericidal effect of aBL combined with a β-lactam antibiotic. Our finds demonstrate that aBL can effectively kill strains carrying β-lactamase genes and reduce the β-lactamase activity. We also demonstrated the role of porphyrins on the photoreaction promoted by aBL and the resulting protein damage. Additionally, ceftazidime activity was significantly improved by aBL in a Metallo-β-lactamase strain. Our finds support the aBL against the β-lactamases and encourage future outcomes.