Study on an injectable biomedical paste using cross-linked sodium hyaluronate as a carrier of hydroxyapatite particles

Preparation of an injectable and photocurable carboxymethyl cellulose/hydroxyapatite composite and its application in cranial regeneration

Limited bone regeneration, uncontrollable degradation rate, mismatched defect zone and poor operability have plagued the reconstruction of irregular bone defect by tissue-engineered materials. A combination of biomimetic scaffolds with hydroxyapatite has gained great popularity in promoting bone regeneration. Therefore, we designed an injectable, photocurable and in-situ curing hydrogel by methacrylic anhydride -modified carboxymethyl cellulose (CMC-MA) loading with spherical hydroxyapatite (HA) to highly simulate the natural bony matrix and match any shape of damaged tissue. The prepared carboxymethyl cellulose-methacrylate/ hydroxyapatite(CMC-MA/HA) composite presented good rheological behavior, swelling ratio and mechanical property under light illumination. Meanwhile, this composite hydrogel promoted effectively proliferation, supported adhesion and upregulated the osteogenic-related genes expression of MC3T3-E1 cells in vitro, as well as the activity of the osteogenic critical protein, Integrin α1, β1, Myosin 9, Myosin 10, BMP-2 and Smad 1 in Integrin/BMP-2 signal pathway. Together, the composite hydrogels realized promotion of bone regeneration, deformity improvement, and the enhanced new bone strength in skull defect. It also displayed a good histocompatibility and stability of subcutaneous implantation in vivo. Overall, this study laid the groundwork for future research into developing a novel biomaterial and a minimally invasive therapeutic strategies for reconstructing bone defects and contour deficiencies.

Phenylboronate-salicylate ester cross-linked self-healing hydrogel composed of modified hyaluronan at physiological pH

Several hydrogels with boronate/diol ester cross-linking have been reported. However, multiple synthetic steps or expensive reagents are required to modify some diol moieties into polymers. Therefore, diol-modified polymers, which are easily and inexpensively prepared via a single-step process, are required for the formation of boronate esters. This study reports a novel hydrogel composed of phenylboronic acid-modified hyaluronic acid and salicylic acid-modified hyaluronic acid. This hydrogel is injectable, can self-heal at physiological pH, and can be easily and inexpensively prepared. The polymer system behaved as a sol at pH 12.0 and a weak gel at pH 9.4 and 11.2, whereas it behaved as a gel over a wide pH range of 4.0-8.2. The viscoelasticity of the system decreased in response to sugar at pH 7.3. Thus, salicylic acid can be considered a promising diol moiety for hydrogel formation via boronate ester cross-linking.

Design and evaluation of 32P-labeled hydroxyapatite nanoparticles for bone tumor therapy

The clinical diagnosis and treatment of malignant bone tumors are still major clinical challenges due to their high incidence are difficulty. Targeted therapies have become a critical approach to treat bone tumors. In recent years, radiopharmaceuticals have been used widely and have shown potent and efficient results in treating bone tumors, among which ³²P and the labeled radiopharmaceuticals play an essential role. In this study, the ³²P-labeled hydroxyapatite (HA) was prepared through chemical synthesis (³²P-Hap) and physical adsorption (³²P-doped-Hap). The in vitro stability of ³²P-labeled HA was analyzed to assess the superiority of the new-found chemical synthesis. The radiolabeling yield and stability of chemical synthesis (97.6 ± 0.5%) were significantly improved compared with physical adsorption (92.7 ± 0.4%). Furthermore, the CT results corroborate that ³²P-Hap (100 μCi) +DOX group has the highest tumor suppression rate and can effectively reduce bone destruction. The results corroborate the effectiveness of the chemical synthesis and validate the application of ³²P-Hap in bone tumors. Therefore, ³²P-Hap (100 μCi) + DOX may be an effective strategy for bone metastasis treatments.

Preparation and adsorption properties of Ni(ii) ion-imprinted polymers based on synthesized novel functional monomer

In this study, a novel functional monomer N-(1-(2,4-difluorophenyl)-2-(1H-1,2,4-triazol-1-yl)ethyl)acrylamide (NDTEA) was designed and synthesized, and was used to prepare Ni(ii) ion-imprinted polymers (Ni(ii)-IIPs). Sixteen kinds of Ni(ii)-IIP (Ni(ii)-IIP1–16) and corresponding non-imprinted polymers (NIP1–16) were prepared by precipitation polymerization method. After optimized condition experiment, Ni(ii)-IIP5 possessed maximum adsorption capacity and better imprinting factor under optimal experimental conditions which indicated by equilibrium adsorption experiments. The morphology and structural characteristics of Ni(ii)-IIP5 were characterized by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET). The adsorption selectivity of Ni(ii)-IIP5 was analyzed by ICP-OES, and the results showed that Ni(ii)-IIP5 had favorable selectivity recognition ability for Ni(ii) when Cu(ii), Co(ii), and Cd(ii) are used as competitive ions. The kinetic experiment indicated that the performance of Ni(ii) adsorption on the surface of Ni(ii)-IIP5 obeyed the pseudo-first-order model, and adsorption equilibrium was attained after 15 min. Isothermal adsorption process fitted to Langmuir and Freundlich isothermal adsorption models, simultaneously. The results showed that Ni(ii)-IIP5 prepared by using a new functional monomer had better permeation selectivity and higher affinity for Ni(ii), which also verified the rationality of the functional monomer design. At the same time, it also provided a broad application prospect for removal of Ni(ii) in complex samples.

Hyaluronic acid facilitates bone repair effects of calcium phosphate cement by accelerating osteogenic expression

Calcium phosphate cements (CPC) are widely anticipated to be an optimum bone repair substitute due to its satisfied biocompatibility and degradability, suitable to be used in minimally invasive treatment of bone defects. However the clinical application of CPC is still not satisfied by its poor cohesiveness and mechanical properties, in particular its osteoinductivity. Hyaluronic acid reinforced calcium phosphate cements (HA/CPC) showed extroadinary potential not only enhancing the compressive strength of the cements but also significantly increasing its osteoinductivity. In our study, the compressive strength of HA/CPC increased significantly when the cement was added 1% hyaluronic acid (denoted as 1-HA/CPC). In the meantime, hyaluronic acid obviously promoted ALP activity, osteogenic related protein and mRNA expression of hBMSCs (human bone marrow mesenchymal stem cells) in vitro, cement group of HA/CPC with 4% hyaluronic acid adding (denoted as 4-HA/CPC) showed optimal enhancement in hBMSCs differentiation. After being implanted in rat tibial defects, 4-HA/CPC group exhibited better bone repair ability and bone growth promoting factors, comparing to pure CPC and 1-HA/CPC groups. The underlying biological mechanism of this stimulation for HA/CPC may be on account of higher osteogenic promoting factors secretion and osteogenic genes expression with hyaluronic acid incorporation. These results indicate that hyaluronic acid is a highly anticipated additive to improve physicochemical properties and osteoinductivity performance of CPCs for minimally invasive healing of bone defects.

ASIA syndrome symptoms induced by gluteal biopolymer injections: Case-series and narrative review

Background

The number of plastic surgery procedures have been rising in the last few years. The morbi-mortality due to illegal use of biopolymers is a public health problem. One of the clinical consequences, foreign body modelling reaction, may be a precursor of ASIA (Autoimmune/Inflammatory disease induced by adjuvants) syndrome.The objective of this article is to present a case-series study of patients who developed ASIA syndrome following gluteal injection with biopolymers and emphasize the importance of toxic exposure in triggering autoimmune responses. A surgical technique used on some of the patients in the study is described.

Methods

A group of thirteen patients, diagnosed with foreign body modelling reaction, who developed ASIA syndrome confirmed by approved criteria was followed between May 2016 and May 2018. The "Butterfly Wings Technique," a new surgical procedure for patients who have medium to severe compromise, was used on five of them.A narrative literature review was done to look for subjects with ASIA syndrome and gluteal biopolymer infiltration.

Results

All the patients in the present case-series with foreign body modelling reaction developed ASIA syndrome. Some of them had a background of familial autoimmunity. Five of the patients were surgically treated and saw a clinical improvement after the extraction of the biopolymer with the proposed technique.The narrative literature review identified 7 articles related to the disease through the database search.

Conclusions

We suggest that foreign body modelling reaction should be considered a precursor to ASIA syndrome. New research projects will be needed in the future to evaluate the factors that determine when ASIA syndrome is triggered in a patient with this reaction.

Design and Characterization of Injectable Poly(Lactic-Co-Glycolic Acid) Pastes for Sustained and Local Drug Release

PURPOSE

We describe the preparation of injectable polymeric paste (IPP) formulations for local and sustained release of drugs. Furthermore, we include the characterization and possible applications of such pastes. Particular attention is paid to characteristics relevant to the successful clinical formulation development, such as viscosity, injectability, degradation, drug release, sterilization, stability performance and pharmacokinetics.

METHODS

Paste injectability was characterized using measured viscosity and the Hagen-Poiseuille equation to determine injection forces. Drug degradation, release and formulation stability experiments were performed in vitro and drug levels were quantified using HPLC-UV methods. Pharmacokinetic evaluation of sustained-release lidocaine IPPs used five groups of six rats receiving increasing doses subcutaneously. An anti-cancer formulation was evaluated in a subcutaneous tumor xenograft mouse model.

RESULTS

The viscosity and injectability of IPPs could be controlled by changing the polymeric composition. IPPs demonstrated good long-term stability and tunable drug-release with low systemic exposure in vivo in rats. Preliminary data in a subcutaneous tumor model points to a sustained anticancer effect.

CONCLUSIONS

These IPPs are tunable platforms for local and sustained delivery of drugs and have potential for further clinical development to treat a number of diseases.