Absorbance measurement is a widely used method to quantify the concentration of an analyte. The integration of absorbance analysis in microfluidic chips could significantly reduce the sample consumption and contribute to the system miniaturization. However, the sensitivity and limit of detection (LoD) of analysis in microfluidic chips with conventional configuration need improvements due to the limited optical pathway and unregulated light propagation. In this work, a 3D-microlens-incorporating microfluidic chip (3D-MIMC) with a greatly extended detection channel was innovatively fabricated using two-photon stereolithography. The fabrication was optimized with a proposed hierarchical modular printing strategy. Due to the incorporation of 3D microlenses, the light coupling efficiency and the signal-to-noise ratio (SNR) were respectively improved approximately 9 and 4 times. An equivalent optical path length (EOL) of 62.9 mm was achieved in a 3.7 μl detection channel for testing tartrazine samples. As a result, the sensitivity and LoD of the 3D-MIMC assay were correspondingly improved by one order of magnitude, compared with those of the 96-well plate assay. Notably, the 3D-MIMC has the potential to be integrated into a general microanalysis platform for multiple applications.
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Optical neural implants allow neuroscientists to access deep brain regions, enabling to decipher complex patterns of neural activity. In this field, the use of optical fibers is rapidly increasing, and the ability to generate high-quality metal patterns on their non-planar surface would further extend their application. Here, we propose to use alternating metal shielding and dielectric confinement to engineer the mode-division properties of tapered optical fiber neural implants.
View Article and Find Full Text PDFFaithful quantum state transfer between telecom photons and microwave frequency mechanical oscillations necessitate a fast conversion rate and low thermal noise. Two-dimensional (2D) optomechanical crystals (OMCs) are favorable candidates that satisfy those requirements. 2D OMCs enable sufficiently high mechanical frequency (1∼10 GHz) to make the resolved-sideband regime achievable, a prerequisite for many quantum protocols.
View Article and Find Full Text PDFSpecimen-induced aberrations limit the penetration depth of standard optical imaging techniques in vivo, mainly due to the propagation of high NA beams in a non-homogenous medium. Overcoming these limitations requires complex optical imaging systems and techniques. Implantable high NA micro-optics can be a solution to tissue induced spherical aberrations, but in order to be implanted, they need to have reduced complexity, offering a lower surface to the host immune reaction.
View Article and Find Full Text PDFBiosens Bioelectron
January 2025
Department of Electrical Engineering (ESAT-MNS), Catholic University of Leuven (KU Leuven), 3001, Leuven, Belgium; KU Leuven, Department of Physics and Astronomy (HF), Celestij€nenlaan 300D, 3001, Leuven, Belgium; Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnology, Arnesano, Italy.
Microneedles have emerged as a highly promising technology for advancing chemical biosensing and drug delivery applications, offering a minimally invasive, efficient, and versatile approach to healthcare innovation. This review provides a comprehensive analysis of photoresin-based microneedles, with a particular focus on SU-8 photoresin due to its favorable mechanical properties, biocompatibility, and ease of fabrication. Advanced techniques for surface modification are discussed to enhance the functionality of microneedles, enabling their application in precise biochemical diagnostics and effective drug therapy.
View Article and Find Full Text PDFAnnu Rev Biomed Eng
January 2025
1School of Engineering, Brown University, Providence, Rhode Island, USA;
The rise in popularity of two-photon polymerization (TPP) as an additive manufacturing technique has impacted many areas of science and engineering, particularly those related to biomedical applications. Compared with other fabrication methods used for biomedical applications, TPP offers 3D, nanometer-scale fabrication dexterity (free-form). Moreover, the existence of turnkey commercial systems has increased accessibility.
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