Publications by authors named "Sebastian Ahn"

Article Synopsis
  • This study looked at a new way to place a tiny device in men's tumors to see how they respond to different cancer drugs.
  • They used a special scan to help put the devices in the right spot, just before surgery to remove the tumors.
  • The results showed that the method was safe and let them see how the tumors reacted to the drugs, which might help doctors make better treatment choices in the future.
View Article and Find Full Text PDF

Systems that can image in three dimensions at cellular resolution and across different locations within an organism may enable insights into complex biological processes, such as immune responses, for which a single location measurement may be insufficient. In this Letter, we describe an in vivo two-site imaging probe (TIP) that can simultaneously image two anatomic sites with a maximum separation of a few centimeters. The TIP consists of two identical bendable graded index (GRIN) lenses and is demonstrated by a two-photon two-color fluorescence imaging system.

View Article and Find Full Text PDF

The lack of reliable predictive biomarkers to guide effective therapy is a major obstacle to the advancement of therapy for high-grade gliomas, particularly glioblastoma (GBM), one of the few cancers whose prognosis has not improved over the past several decades. With this pilot clinical trial (number NCT04135807), we provide first-in-human evidence that drug-releasing intratumoral microdevices (IMDs) can be safely and effectively used to obtain patient-specific, high-throughput molecular and histopathological drug response profiling. These data can complement other strategies to inform the selection of drugs based on their observed antitumor effect in situ.

View Article and Find Full Text PDF
Article Synopsis
  • Tumor-infiltrating immune cells and cancer cells compete for nutrients in the tumor microenvironment, leading to metabolic reprogramming that affects their functions.
  • The study introduced a new method using implantable microdevices to analyze how different metabolites impact the health and endurance of immune versus tumor cells within the native tumor environment.
  • Key findings highlight the importance of metabolites like glutamine and arginine in enhancing immune responses, and suggest that optimizing these metabolic pathways could improve the effectiveness of immunotherapies in cancer treatment.
View Article and Find Full Text PDF

Graded index (GRIN) lens endoscopy has broadly benefited biomedical microscopic imaging by enabling accessibility to sites not reachable by traditional benchtop microscopes. It is a long-held notion that GRIN lenses can only be used as rigid probes, which may limit their potential for certain applications. Here, we describe bendable and long-range GRIN microimaging probes for a variety of potential micro-endoscopic biomedical applications.

View Article and Find Full Text PDF

Systematically identifying synergistic combinations of targeted agents and immunotherapies for cancer treatments remains difficult. In this study, we integrated high-throughput and high-content techniques-an implantable microdevice to administer multiple drugs into different sites in tumors at nanodoses and multiplexed imaging of tumor microenvironmental states-to investigate the tumor cell and immunological response signatures to different treatment regimens. Using a mouse model of breast cancer, we identified effective combinations from among numerous agents within days.

View Article and Find Full Text PDF

Long-term treatment outcomes for patients with high grade ovarian cancers have not changed despite innovations in therapies. There is no recommended assay for predicting patient response to second-line therapy, thus clinicians must make treatment decisions based on each individual patient. Patient-derived xenograft (PDX) tumors have been shown to predict drug sensitivity in ovarian cancer patients, but the time frame for intraperitoneal (IP) tumor generation, expansion, and drug screening is beyond that for tumor recurrence and platinum resistance to occur, thus results do not have clinical utility.

View Article and Find Full Text PDF

A main impediment to effective development of new therapeutics for central nervous system disorders, and for the testing of biological hypotheses in the brain, is the ability to rapidly measure the effect of novel agents and treatment combinations on the pathophysiology of native brain tissue. We have developed a miniaturized implantable microdevice (IMD) platform, optimized for direct stereotactic insertion into the brain, which enables the simultaneous measurement of multiple drug effects on the native brain tissue . The IMD contains individual reservoirs which release microdoses of single agents or combinations into confined regions of the brain, with subsequent spatial analysis of phenotypic, transcriptomic or metabolomic effects.

View Article and Find Full Text PDF

Objective: To evaluate the safety and feasibility of implantation and retrieval of a novel implantable microdevice (IMD) in NSCLC patients undergoing operative resection.

Background: Adjuvant therapy has limited impact on postsurgical outcomes in NSCLC due to the inability to predict optimal treatment regimens.

Methods: An IMD measuring 6.

View Article and Find Full Text PDF

Advances in the intratumor measurement of drug responses have included a pioneering biomedical microdevice for high throughput drug screening in vivo, which was further advanced by integrating a graded-index lens based two-dimensional fluorescence micro-endoscope to monitor tissue responses in situ across time. While the previous system provided a bulk measurement of both drug delivery and tissue response from a given region of the tumor, it was incapable of visualizing drug distribution and tissue responses in a three-dimensional (3D) way, thus missing the critical relationship between drug concentration and effect. Here we demonstrate a next-generation system that couples multiplexed intratumor drug release with continuous 3D spatial imaging of the tumor microenvironment via the integration of a miniaturized two-photon micro-endoscope.

View Article and Find Full Text PDF

Background: Tumor heterogeneity is increasingly being recognized as a major source of variability in the histopathological assessment of drug responses. Quantitative analysis of immunohistochemistry (IHC) and immunofluorescence (IF) images using biomarkers that capture spatialpatterns of distinct tumor biology and drug concentration in tumors is of high interest to the field.

Methods: We have developed an image analysis pipeline to measure drug response using IF and IHC images along spatial gradients of local drug release from a tumor-implantable drug delivery microdevice.

View Article and Find Full Text PDF

By observing the activity of anti-cancer agents directly in tumors, there is potential to greatly expand our understanding of drug response and develop more personalized cancer treatments. Implantable microdevices (IMD) have been recently developed to deliver microdoses of chemotherapeutic agents locally into confined regions of live tumors; the tissue can be subsequently removed and analyzed to evaluate drug response. This method has the potential to rapidly screen multiple drugs, but requires surgical tissue removal and only evaluates drug response at a single timepoint when the tissue is excised.

View Article and Find Full Text PDF