Specific enrichment combined with highly efficient solid-phase tagging for the sensitive detection of heparin based on boronic acid-functionalized mesoporous silica nanospheres

Enhanced Photoacoustic Detection of Heparin in Whole Blood via Melanin Nanocapsules Carrying Molecular Agents

Photoacoustic (PA) imaging has proved versatile for many biomedical applications from drug delivery tracking to disease diagnostics and postoperative surveillance. It recently emerged as a tool for accurate and real-time heparin monitoring to avoid bleeding complications associated with anticoagulant therapy. However, molecular-dye-based application is limited by high concentration requirements, photostability, and a strong background hemoglobin signal. We developed polydopamine nanocapsules (PNCs) via supramolecular templates and loaded them with molecular dyes for enhanced PA-mediated heparin detection. Depending on surface charge, the dye-loaded PNCs undergo disassembly or aggregation upon heparin recognition: both experiments and simulation have revealed that the increased PA signal mainly results from dye-loaded PNC-heparin aggregation. Importantly, Nile blue (NB)-loaded PNCs generated a 10-fold higher PA signal than free NB dye, and such PNC enabled the direct detection of heparin in a clinically relevant therapeutic window (0-4 U/mL) in whole human blood (R² = 0.91). Furthermore, the PA signal of PNC@NB obtained from 17 patients linearly correlated with ACT values (R² = 0.73) and cumulative heparin (R² = 0.83). This PNC-based strategy for functional nanocapsules offers a versatile engineering platform for robust biomedical contrast agents and nanocarriers.

Connecting the Dynamics and Reactivity of Arylboronic Acids to Emergent and Stimuli-Responsive Material Properties

Over the past two decades, arylboronic acid-functionalized biomaterials have been used in a variety of sensing and stimuli-responsive scaffolds. Their diverse applications result from the diverse reactivity of arylboronic acids,...

Hyaluronic Acid-Functionalized Hollow Mesoporous Silica Nanoparticles as pH-Sensitive Nanocarriers for Cancer Chemo-Photodynamic Therapy

Hollow mesoporous silica nanoparticles (HMSNs) served as nanocarriers for transporting doxorubicin hydrochloride (DOX) and indocyanine green (ICG) and were incorporated into a pH-sensitive targeted drug delivery system (DDS). Boronate ester bonds were employed to link HMSNs and dopamine-modified hyaluronic acid (DA-HA), which acted as both the "gatekeeper" and targeting agents (HMSNs-B-HA). Well-dispersed HMSNs-B-HA with a diameter of about 170 nm was successfully constructed. The conclusion was drawn from the in vitro drug release experiment that ICG and DOX (ID) co-loaded nanoparticles (ID@HMSNs-B-HA) with high drug loading efficiency could sustain drug release under acidic conditions. More importantly, in vitro cell experiments perfectly showed that ID@HMSNs-B-HA could well inhibit murine mammary carcinoma (4T1) cells via chemotherapy combined with photodynamic therapy and accurately target 4 T1 cells. In summary, all test results sufficiently demonstrated that the prepared ID@HMSNs-B-HA was a promising nano-DDS for cancer photodynamic combined with chemotherapy.

Fluorometric 'switch-on' detection of heparin based on a system composed of rhodamine-labeled chitosan oligosaccharide lactate, and graphene oxide

A novel fluorescence 'Switch on' for the detection of heparin based on the RhB-COL/GO system was achieved. A strong fluorescence dye, Rhodamine B, was modified by chitosan oligosaccharide lactate (COL), which plays a major role in the formation of a positively charged RhB-COL complex. RhB-COL was soluble and stable in solution, which was characterized by using Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. GO sheets quenched the fluorescence intensity of RhB-COL due to electron transfer from RhB to the GO surface. The decrease in fluorescence intensity of RhB-COL with increasing GO concentration was recorded using a Cary Eclipse fluorescence spectrophotometer. On the other hand, the addition of heparin replaced GO to bind with the RhB-COL surface via an electrostatic and noncovalent bond due to the abundant negative charge, which resulted in recovery of the fluorescence intensity. This RhB-COL/GO system possessed high selectivity and good sensitivity for the detection of heparin compared to other biomolecules, such as glycine, D-glucose, hyaluronic acid, L-glutamic acid, and ascorbic acid. The linear response toward heparin was measured over the range, 0-1.8 U · ml^-1, with a low detection limit of 0.04 U · ml^-1. The satisfactory sensing performance of RhB-COL/GO for heparin supports new 'switch-on' sensor applications in heparin-related biomedical detection.

A Turn-on Fluorescence Sensor for Heparin Detection Based on a Release of Taiwan Cobra Cardiotoxin from a DNA Aptamer or Adenosine-Based Molecular Beacon

This study presents two sensitive fluorescent assays for sensing heparin on the basis of the electrostatic interaction between heparin and Naja naja atra cardiotoxin 3 (CTX3). Owing to CTX3-induced folded structure of an adenosine-based molecular beacon (MB) or a DNA aptamer against CTX3, a reduction in the fluorescent signal of the aptamer or MB 5'-end labeled with carboxyfluorescein (FAM) and 3'-end labeled with 4-([4-(dimethylamino)phenyl]azo)-benzoic acid (DABCYL) was observed upon the addition of CTX3. The presence of heparin and formation of the CTX3-heparin complex caused CTX3 detachment from the MB or aptamer, and restoration of FAM fluorescence of the 5'-FAM-and-3'-DABCYL-labeled MB and aptamer was subsequently noted. Moreover, the detection of heparin with these CTX3-aptamer and CTX3-MB sensors showed high sensitivity and selectivity toward heparin over chondroitin sulfate and hyaluronic acid regardless of the presence of plasma. The limit of detection for heparin in plasma was determined to be 16 ng/mL and 15 ng/mL, respectively, at a signal-to-noise ratio of 3. This study validates the practical utility of the CTX3-aptamer and CTX3-MB systems for determining the concentration of heparin in a biological matrix.

Rapid and visual detection of heparin based on the disassembly of polyelectrolyte-induced pyrene excimers

A sensor based on polyelectrolyte-induced pyrene excimers has been developed for the visual detection of heparin with high sensitivity and selectivity.