(499f) Multifunctional 3D-Printed Microbeads for Sample Preparation and Non-Contact Thermal Sensing in Point-of-Care Diagnostics

Sample preparation remains a critical bottleneck in point-of-care (POC) diagnostic platforms, particularly for complex biological samples like saliva or blood, where nucleic acid extraction often demands multiple steps such as centrifugation or costly commercial kits (e.g., Qiagen beads). These requirements hinder rapid, affordable testing in resource-limited settings. To overcome this, we utilized masked stereolithography (MSLA) 3D printing with a photocurable resin to fabricate sub-millimeter-scale microbeads featuring tunable surface morphology. The printing process is optimized to create structures, which are subsequently functionalized with amino-silane to enable DNA binding. We demonstrate that these beads effectively capture and concentrate DNA from crude saliva samples, simplifying extraction without centrifugation or expensive reagents, thus streamlining POC workflows.

Beyond DNA extraction, we engineered similar beads incorporated with temperature-sensitive fluorophores, such as Rhodamine B (RhB), preserving their quantum yield during MSLA printing. By controlling cross-linking density and mixing homogeneity, we produced beads and microscale features that exhibit fluorescence intensity-based temperature sensitivity. Using a custom fluorescence microscope for simultaneous heating and imaging, we achieved non-contact thermometry within microfluidic channels—ideal for monitoring thermal conditions in diagnostic assays. Additionally, we mixed carbon dots into the resin to create photothermally active microbeads. When exposed to light, these beads absorb energy and convert it into heat via photothermal effects, enabling non-contact heating of surrounding fluids or samples. Characterized for material strength and surface properties, these beads offer precise thermal control in microscale systems without external heaters. Together, these advancements—DNA-binding beads, fluorescence-based thermometry, and photothermal heating—provide a versatile, low-cost platform that enhances sample preparation and thermal management, paving the way for integrated, portable POC diagnostics.