Dopamine-functionalized hyaluronic acid microspheres for effective capture of CD44-overexpressing circulating tumor cells

Mechanically tough, adhesive, self-healing hydrogel promotes annulus fibrosus repair via autologous cell recruitment and microenvironment regulation

Annulus fibrosus (AF) defect is an important cause of disc re-herniation after discectomy. The self-regeneration ability of the AF is limited, and AF repair is always hindered by the inflammatory microenvironment after injury. Hydrogels represent one of the most promising materials for AF tissue engineering strategies. However, currently available commercial hydrogels cannot withstand the harsh mechanical load within intervertebral disc. In the present study, an innovative triple cross-linked oxidized hyaluronic acid (OHA)-dopamine (DA)- polyacrylamide (PAM) composite hydrogel, modified with collagen mimetic peptide (CMP) and supplied with transforming growth factor beta 1 (TGF-β1) (OHA-DA-PAM/CMP/TGF-β1 hydrogel) was developed for AF regeneration. The hydrogel exhibited robust mechanical strength, strong bioadhesion, and significant self-healing capabilities. Modified with collagen mimetic peptide, the hydrogel exhibited extracellular-matrix-mimicking properties and sustained the AF cell phenotype. The sustained release of TGF-β1 from the hydrogel was pivotal in recruiting AF cells and promoting extracellular matrix production. Furthermore, the composite hydrogel attenuated LPS-induced inflammatory response and promote ECM synthesis in AF cells via suppressing NFκB/NLRP3 pathway. In vivo, the composite hydrogel successfully sealed AF defects and alleviated intervertebral disk degeneration in a rat tail AF defect model. Histological evaluation showed that the hydrogel integrated well with host tissue and facilitated AF repair. The strategy of recruiting endogenous cells and providing an extracellular-matrix-mimicking and anti-inflammatory microenvironment using the mechanically tough composite OHA-DA-PAM/CMP/TGF-β1 hydrogel may be applicable for AF defect repair in the clinic. STATEMENT OF SIGNIFICANCE: Annulus fibrosus (AF) repair is challenging due to its limited self-regenerative capacity and post-injury inflammation. In this study, a mechanically tough and highly bioadhesive triple cross-linked composite hydrogel, modified with collagen mimetic peptide (CMP) and supplemented with transforming growth factor beta 1 (TGF-β1), was developed to facilitate AF regeneration. The sustained release of TGF-β1 enhanced AF cell recruitment, while both TGF-β1 and CMP could modulate the microenvironment to promote AF cell proliferation and ECM synthesis. In vivo, this composite hydrogel effectively promoted the AF repair and mitigated the intervertebral disc degeneration. This research indicates the clinical potential of the OHA-DA-PAM/CMP/TGF-β1 composite hydrogel for repairing AF defects.

Selection of DNA aptamer recognizing CD44 for high-efficiency capture of circulating tumor cells

Cancer stem cells play critical roles in cancer progression, cancer invasion and metastasis, and cancer recurrence. CD44 is known as a specific surface marker of cancer stem cells, which has been well-studied in cancer invasion and metastasis. Herein, we successfully selected the DNA aptamers for recognizing CD44⁺ cells using Cell-SELEX strategy, in which the engineered CD44 overexpression cells were used as target cells for selection. The optimized aptamer candidate C24S showed high binding affinity with the K_d value of 14.54 nM and good specificity. Then, the aptamer C24S was employed to prepare the functional aptamer-magnetic nanoparticles (C24S-MNPs) for CTC capture. To investigate the capture efficiency and sensitivity of C24S-MNPs, series of cell capture tests were performed using artificial samples with 10-200 of HeLa cells spiked into 1 mL PBS or PBMCs isolated from 1 mL peripheral blood, obtaining an efficiency of 95% and 90%, respectively. More importantly, we finally explored the facility of C24S-MNPs for CTC detection in blood samples from clinical cancer patients, indicating a potential and feasible strategy for cancer diagnostic technology in clinical applications.

Polysaccharide-modified liposomes and their application in cancer research

Nanodrug delivery systems have been widely used in cancer treatment. Among these, liposomal drug carriers have gained considerable attention due to their biocompatibility, biodegradability, and low toxicity. However, conventional liposomes have several shortcomings, such as poor stability, rapid clearance, aggregation, fusion, degradation, hydrolysis, and oxidation of phospholipids. Polysaccharides are natural polymers of biological origin that exhibit structural stability, excellent biocompatibility and biodegradability, flexibility, non-immunogenicity, low toxicity, and targetability. Therefore, they represent a promising class of polymers for the modification of the surface properties of liposomes to overcome their shortcomings. In addition, polysaccharides can be readily combined with other materials to develop new composite materials. Hence, they represent the optimal choice for liposomal modification to improve pharmacokinetics and clinical utility. Polysaccharide-coated liposomes exhibit better stability, drug release kinetics, and cellular uptake than conventional liposomes. The oncologic application of polysaccharide-coated liposomes has become a research hotspot. We summarize the preparation, physicochemical properties, and antineoplastic effects of polysaccharide-coated liposomes to facilitate antitumor drug development.

Recent progress of nanostructure-based enrichment of circulating tumor cells and downstream analysis

The isolation and detection of circulating tumor cells (CTCs) play an important role in early cancer diagnosis and prognosis, providing easy access to identify metastatic cells before clinically detectable metastases. In the past 20 years, according to the heterogeneous expression of CTCs on the surface and their special physical properties (size, morphology, electricity, etc.), a series of in vitro enrichment methods of CTCs have been developed based on microfluidic chip technology, nanomaterials and various nanostructures. In recent years, the in vivo detection of CTCs has attracted considerable attention. Photoacoustic flow cytometry and fluorescence flow cytometry were used to detect CTCs in a noninvasive manner. In addition, flexible magnetic wire and indwelling intravascular non-circulating CTCs isolation system were developed for in vivo CTCs study. In the aspect of downstream analysis, gene analysis and drug sensitivity tests of enriched CTCs were developed based on various existing molecular analysis techniques. All of these studies constitute a complete study of CTCs. Although the existing reviews mainly focus on one aspect of capturing CTCs study, a review that includes the in vivo and in vitro capture and downstream analysis study of CTCs is highly needed. This review focuses on not only the classic work and latest research progress in in vitro capture but also includes the in vivo capture and downstream analysis, discussing the advantages and significance of the different research methods and providing new ideas for solving the heterogeneity and rarity of CTCs.

Curcumin-Loaded Platelet Membrane Bioinspired Chitosan-Modified Liposome for Effective Cancer Therapy

Cancer is a serious threat to human health, and chemotherapy for cancer is limited by severe side effects. Curcumin (CUR) is a commonly used natural product for antitumor treatment without safety concerns. However, low bioavailability and poor tumor accumulation are great obstacles for its clinical application. Our previous research has demonstrated that platelet membrane-camouflaged nanoparticles can efficiently ameliorate the in vivo kinetic characteristics and enhance the tumor affinity of payloads. Nevertheless, the antitumor efficiency of this formulation still needs to be thoroughly investigated, and its drug release behavior is limited. Herein, CUR-loaded platelet membrane bioinspired chitosan-modified liposome (PCLP-CUR) was constructed to improve CUR release. PCLP-CUR was shown to have long retention time, improved bioavailability, strong tumor targeting capacity and effective cellular uptake. The incorporation of chitosan enabled PCLP-CUR to release cargoes quickly under mild acidic tumor conditions, leading to more complete drug release and favoring subsequent treatment. Both in vitro and in vivo investigations showed that PCLP-CUR could significantly enhance the anticancer efficacy of CUR with minimal side effects through biomimetic membrane and chitosan modification. In summary, this developed delivery system can provide a promising strategy for tumor-targeting therapy and phytochemical delivery.

Renewable marine polysaccharides for microenvironment-responsive wound healing

Marine polysaccharides (MPs) are an eco-friendly and renewable resource with a distinctive set of biological functions and are regarded as biological materials that can be in contact with tissues and body fluids for an extended time and promote tissue or organ regeneration. Skin tissue is easily invaded by the external environment due to its softness and large surface area. However, the body's natural physiological healing process is often too slow or suffers from the incomplete restoration of skin structure and function. Functional wound dressings are crucial for skin tissue engineering. Herein, popular MPs from different sources are summarized systematically. In particular, the structure-effectiveness of MP-based wound dressings and the physiological remodeling process of different wounds are reviewed in detail. Finally, the prospect of MP-based smart wound dressings is stated in conjunction with the wound microenvironment and provides new opportunities for high-value biomedical applications of MPs.

Advances in Hyaluronic Acid for Biomedical Applications

Hyaluronic acid (HA) is a large non-sulfated glycosaminoglycan that is the main component of the extracellular matrix (ECM). Because of its strong and diversified functions applied in broad fields, HA has been widely studied and reported previously. The molecular properties of HA and its derivatives, including a wide range of molecular weights but distinct effects on cells, moisture retention and anti-aging, and CD44 targeting, promised its role as a popular participant in tissue engineering, wound healing, cancer treatment, ophthalmology, and cosmetics. In recent years, HA and its derivatives have played an increasingly important role in the aforementioned biomedical fields in the formulation of coatings, nanoparticles, and hydrogels. This article highlights recent efforts in converting HA to smart formulation, such as multifunctional coatings, targeted nanoparticles, or injectable hydrogels, which are used in advanced biomedical application.

Bioactive Decellularized Extracellular Matrix Hydrogel Microspheres Fabricated Using a Temperature-Controlling Microfluidic System

Hydrogel microspheres have drawn great attention as functional three-dimensional (3D) microcarriers for cell attachment and growth, which have shown great potential in cell-based therapies and biomedical research. Hydrogels derived from a decellularized extracellular matrix (dECM) retain the intrinsic physical and biological cues from the native tissues, which often exhibit high bioactivity and tissue-specificity in promoting tissue regeneration. Herein, a novel two-stage temperature-controlling microfluidic system was developed which enabled production of pristine dECM hydrogel microspheres in a high-throughput manner. Porcine decellularized peripheral nerve matrix (pDNM) was used as the model raw dECM material for continuous generation of pDNM microgels without additional supporting materials or chemical crosslinking. The sizes of the microspheres were well-controlled by tuning the feed ratios of water/oil phases into the microfluidic device. The resulting pDNM microspheres (pDNM-MSs) were relatively stable, which maintained a spherical shape and a nanofibrous ultrastructure for at least 14 days. Schwann cells and PC12 cells preseeded on the pDNM-MSs not only showed excellent viability and an adhesive property, but also promoted cell extension compared to the commercially available gelatin microspheres. Moreover, primary neural stem/progenitor cells attached well to the pDNM-MSs, which further facilitated their proliferation. The successfully fabricated dECM hydrogel microspheres provided a highly bioactive microenvironment for 3D cell culture and functionalization, which showed promising potential in versatile biomedical applications.

Dopamine-conjugated hyaluronic acid delivered via intra-articular injection provides articular cartilage lubrication and protection

Due to its high molecular weight and viscosity, hyaluronic acid (HA) is widely used for viscosupplementation to provide joint pain relief in osteoarthritis. However, this benefit is temporary due to poor adhesion of HA on articular surfaces. In this study, we therefore conjugated HA with dopamine to form HADN, which made the HA adhesive while retaining its viscosity enhancement capacity. We hypothesized that HADN could enhance cartilage lubrication through adsorption onto the exposed collagen type II network and repair the lamina splendens. HADN was synthesized by carbodiimide chemistry between hyaluronic acid and dopamine. Analysis of Magnetic Resonance (NMR) and Ultraviolet spectrophotometry (Uv-vis) showed that HADN was successfully synthesized. Adsorption of HADN on collagen was demonstrated using Quartz crystal microbalance with dissipation (QCM-D). Ex vivo tribological tests including measurement of coefficient of friction (COF), dynamic creep, in stance (40 N) and swing (4 N) phases of gait cycle indicated adequate protection of cartilage by HADN with higher lubrication compared to HA alone. HADN solution at the cartilage-glass sliding interface not only retains the same viscosity as HA and provides fluid film lubrication, but also ensures better boundary lubrication through adsorption. To confirm the cartilage surface protection of HADN, we visualized cartilage wear using optical coherence tomography (OCT) and atomic force microscopy (AFM).

Hyaluronic acid-coated chitosan nanoparticles as carrier for the enzyme/prodrug complex based on horseradish peroxidase/indole-3-acetic acid: Characterization and potential therapeutic for bladder cancer cells

Hybrid nanoparticles composed of different biopolymers for delivery of enzyme/prodrug systems are of interest for cancer therapy. Hyaluronic acid-coated chitosan nanoparticles (CS/HA NP) were prepared to encapsulate individually an enzyme/pro-drug complex based on horseradish peroxidase (HRP) and indole-3-acetic acid (IAA). CS/HA NP showed size around 158 nm and increase to 170 and 200 nm after IAA and HRP encapsulation, respectively. Nanoparticles showed positive zeta potential values (between +20.36 mV and +24.40 mV) and higher encapsulation efficiencies for both nanoparticles (up to 90 %) were obtained. Electron microscopy indicated the formation of spherical particles with smooth surface characteristic. Physicochemical and thermal characterizations suggest the encapsulation of HRP and IAA. Kinetic parameters for encapsulated HRP were similar to those of the free enzyme. IAA-CS/HA NP showed a bimodal release profile of IAA with a high initial release (72 %) followed by a slow-release pattern. The combination of HRP-CS/HA NP and IAA- CS/HA NP reduced by 88 % the cell viability of human bladder carcinoma cell line (T24) in the concentrations 0.5 mM of pro-drug and 1.2 μg/mL of the enzyme after 24 h.

PtS2 nanosheets as a peroxidase-mimicking nanozyme for colorimetric determination of hydrogen peroxide and glucose

Using an ultrasonication-assisted liquid exfoliation method, we have synthesized PtS₂ nanosheets with good reproducibility. Herein, intrinsic peroxidase-like activity was for the first time demonstrated for PtS₂ nanosheets, which can catalyze H₂O₂ oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to generate a colored solution. The catalytic mechanism of PtS₂ nanosheets was investigated, which indicated that acceleration of the electron transfer between TMB and H₂O₂ was the main reason for the peroxidase-like activity of PtS₂ nanosheets. Based on these observations, we exploited PtS₂ nanosheets integrated into dopamine-functionalized hyaluronic acid (HA-DA) hydrogel microspheres by droplet microfluidics to construct PtS₂ nanosheet- and PtS₂@HA-DA microsphere-based sensors for highly sensitive determination of H₂O₂. When coupled with glucose oxidase, we further developed two glucose sensors based on the above two methods. Among them, the linearity of the PtS₂ nanosheet-based spectrophotometry was in the range of 0.5 to 150 μM and the limit of detection as low as 0.20 μM. The linearity of the microsphere-based colorimetry was in the range 200 to 12,000 μM with a detection limit of 29.95 μM. Both of the glucose sensors can be applied to the determination of glucose in human serum with reliable results and reproducibility.

Adhesive Catechol-Conjugated Hyaluronic Acid for Biomedical Applications: A Mini Review

Recently, catechol-containing polymers have been extensively developed as promising materials for surgical tissue adhesives, wound dressing, drug delivery depots, and tissue engineering scaffolds. Catechol conjugation to the polymer backbone provides adhesive properties to the tissue and does not significantly affect the intrinsic properties of the polymers. An example of a catecholic polymer is catechol-conjugated hyaluronic acid. In general, hyaluronic acid shows excellent biocompatibility and biodegradability; thus, it is used in various medical applications. However, hyaluronic acid alone has poor mechanical and tissue adhesion properties. Catechol modification considerably increases the mechanical and underwater adhesive properties of hyaluronic acid, while maintaining its biocompatibility and biodegradability and enabling its use in several biomedical applications. In this review, we briefly describe the synthesis and characteristics of catechol-modified hyaluronic acid, with a specific focus on catechol-involving reactions. Finally, we discuss the basic concepts and therapeutic effects of catechol-conjugated hyaluronic acid for biomedical applications.