Cold Atmospheric Plasma Activates Selective Photothermal Therapy of Cancer.

Due to the body's systemic distribution of photothermal agents (PTAs), and to the imprecise exposure of lasers, photothermal therapy (PTT) is challenging to use in treating tumor sites selectively. Striving for PTT with high selectivity and precise treatment is nevertheless important, in order to raise the survival rate of cancer patients and lower the likelihood of adverse effects on other body sections. Here, we studied cold atmospheric plasma (CAP) as a supplementary procedure to enhance selectivity of PTT for cancer, using the classical photothermic agent's gold nanostars (AuNSs). In in vitro experiments, CAP decreases the effective power of PTT: the combination of PTT with CAP at lower power has similar cytotoxicity to that using higher power irradiation alone. In in vivo experiments, combination therapy can achieve rapid tumor suppression in the early stages of treatment and reduce side effects to surrounding normal tissues, compared to applying PTT alone. This research provides a strategy for the use of selective PTT for cancer, and promotes the clinical transformation of CAP.

Co-delivery of docetaxel and p53 gene from cationic nanoparticles based on poly (l-lactide) and low-molecular-weight polyethyleneimine (PEA).

Recent findings revealed that low-concentration paclitaxel(DTX) could enhance cytotoxicity by upregulating p53 expression in lung cancer cell lines. So, co-delivery of DTX and RFP-p53 gene with PEA nanoparticles (NPs) was studied. The prepared DTX loaded PEA NPs (PEA/DTX) were characterized by particle size distribution, morphology, zeta potential, and crystallography and cytotoxicity. Results showed that the PEA/DTX NPs had a mall particle size (≤100 nm), moderate zeta potential (≥40 mV) and drug loading of 9.0%, DTX was released from PEA/DTX NPs in an extended period in vitro. More important, agarose gel electrophoresis showed that PEA/DTX cationic NPs were able to completely bind RFP-p53 gene with mean particles size and zeta potential. Studies on cellular uptake of (PEA/DTX)/RFP-p53 NPs demonstrated that both drug and gene were effectively taken up by A549 tumor cells. It was found that intravenous injection of (PEA/DTX)/RFP-p53 NPs efficiently inhibited growth of subcutaneous A549 carcinoma in vivo (p < 0.05) and was significantly less side effect than that of mice treated with the other groups. Therefore, the (PEA/DTX)/RFP-p53 NPs might be a promising candidate for A549 cancer therapy.

LINC01134: a pivotal oncogene with promising predictive maker and therapeutic target in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) represents a leading and fatal malignancy within the gastrointestinal tract. Recent advancements highlight the pivotal role of long non-coding RNAs (lncRNAs) in diverse biological pathways and pathologies, particularly in tumorigenesis. LINC01134, a particular lncRNA, has attracted considerable attention due to its oncogenic potential in hepatoma. Current research underscores LINC01134's potential in augmenting the onset and progression of HCC, with notable implications in drug resistance. This review comprehensively explores the molecular functions and regulatory mechanisms of LINC01134 in HCC, offering a fresh perspective for therapeutic interventions. By delving into LINC01134's multifaceted roles, we aim to foster novel strategies in HCC management.

Olfactory ensheathing cells as candidate cells for chronic pain treatment.

Chronic pain is often accompanied by tissue damage and pain hypersensitivity. It easily relapses and is challenging to cure, which seriously affects the patients' quality of life and is an urgent problem to be solved. Current treatment methods primarily rely on morphine drugs, which do not address the underlying nerve injury and may cause adverse reactions. Therefore, in recent years, scientists have shifted their focus from chronic pain treatment to cell transplantation. This review describes the classification and mechanism of chronic pain through the introduction of the characteristics of olfactory ensheathing cells (OECs), an in-depth discussion of special glial cells through the phagocytosis of nerve debris, receptor-ligand interactions, providing nutrition, and other inhibition of neuroinflammation, and ultimately supporting axon regeneration and mitigation of chronic pain. This review summarizes the potential and limitations of OECs for treating chronic pain by objectively analyzing relevant clinical trials and methods to enhance efficacy and future development prospects.

Synthesis, characterization, and application of amino-terminated poly(ethylene glycol)-block-poly(epsilon-caprolactone) copolymer for paclitaxel.

In this paper, we successfully synthesized amino-terminated poly(ethylene glycol)-block-poly (epsilon-caprolactone) (NH2-PEG-PCL) block copolymer from polyethylene glycol 2000, epsilon-caprolactone (epsilon-CL) and hydrazine hydrate. The obtained copolymer was characterized by nuclear magnetic resonance (1H-NMR), the molecular weight and distribution of NH2-PEG-PCL were characterized by Gel permeation chromatography (GPC). The NH2-PEG-PCL copolymer could self-assemble into micelles in water. Paclitaxel (PTX) loaded NH2-PEG-PCL (PNPP) micelles were prepared by solid dispersion technique without organic solvent. The micelles were characterized by XRD, TEM and Malvern laser particle size. The results of this work indicated that PNPP micelles were uniform and spherical shapes in solution. The average size and zeta potential of PNPP (DL = 8%) in water was about 97.1 +/- 1.2 nm, +13.9 +/- 0.6 mV, respectively. The in vitrodrug release profile of PNPP micelles showed a clear slow-release effect. The results suggested that NH2-PEG-PCL copolymer might be an excellent carrier for hydrophobic drugs such as PTX. In particular, the NH2-PEG-PCL polymer has potential value for modifying with ligands to work as active targeting drug delivery carriers, which has great significance for cancer therapeutics.

Comparisons of three polyethyleneimine-derived nanoparticles as a gene therapy delivery system for renal cell carcinoma.

BACKGROUND: Polyethyleneimine (PEI), which can interact with negatively charged DNA through electrostatic interaction to form nanocomplexes, has been widely attempted to use as a gene delivery system. However, PEI has some defects that are not fit for keeping on gene expression. Therefore, some modifications against PEI properties have been done to improve their application value in gene delivery. In this study, three modified PEI derivatives, including poly(ε-caprolactone)-pluronic-poly(ε-caprolactone) grafted PEI (PCFC-g-PEI), folic acid-PCFC-isophorone diidocyanate-PEI (FA-PEAs) and heparin-PEI (HPEI), were evaluated in terms of their cytotoxicity and transfection efficiency in vitro and in vivo in order to ascertain their potential application in gene therapy. METHODS: MTT assay and a marker GFP gene, encoding green fluorescent protein, were used to evaluate cell toxicity and transfection activity of the three modified PEI in vitro. Renal cell carcinoma (RCC) models were established in BALB/c nude mice inoculated with OS-RC-2 cells to detect the gene therapy effects using the three PEI-derived nanoparticles as gene delivery vehicles. The expression status of a target gene Von Hippel-Lindau (VHL) in treated tumor tissues was analyzed by semiquantitative RT-PCR and immunohistochemistry. RESULTS: Each of three modified PEI-derived biomaterials had an increased transfection efficiency and a lower cytotoxicity compared with its precursor PEI with 25-kD or 2-kD molecule weight in vitro. And the mean tumor volume was obviously decreased 30% by using FA-PEAs to transfer VHL plasmids to treat mice RCC models. The VHL gene expression was greatly improved in the VHL-treated group. While there was no obvious tumor inhibition treated by PCFC-g-PEI:VHL and HPEI:VHL complexes. CONCLUSIONS: The three modified PEI-derived biomaterials, including PCFC-g-PEI, FA-PEAs and HPEI, had an increased transfection efficiency in vitro and obviously lower toxicities compared with their precursor PEI molecules. The FA-PEAs probably provide a potential gene delivery system to treat RCC even other cancers in future.

A novel poly(epsilon-caprolactone)-pluronic-poly(epsilon-caprolactone) grafted polyethyleneimine(PCFC-g-PEI), Part 1, synthesis, cytotoxicity, and in vitro transfection study.

BACKGROUND: Polyethyleneimine (PEI), a cationic polymer, is one of the successful and widely used vectors for non-viral gene transfection in vitro. However, its in vivo application was greatly limited due to its high cytotoxicity and short duration of gene expression. To improve its biocompatibility and transfection efficiency, PEI has been modified with PEG, folic acid, and chloroquine in order to improve biocompatibility and enhance targeting. RESULTS: Poly(epsilon-caprolactone)-Pluronic-Poly(epsilon-caprolactone) (PCFC) was synthesized by ring-opening polymerization, and PCFC-g-PEI was obtained by Michael addition reaction with GMA-PCFC-GMA and polyethyleneimine (PEI, 25 kD). The prepared PCFC-g-PEI was characterized by 1H-NMR, SEC-MALLS. Meanwhile, DNA condensation, DNase I protection, the particle size and zeta potential of PCFC-g-PEI/DNA complexes were also determined. According to the results of flow cytometry and MTT assay, the synthesized PCFC-g-PEI, with considerable transfection efficiency, had obviously lower cytotoxicity against 293 T and A549 cell lines compared with that of PEI 25 kD. CONCLUSION: The cytotoxicity and in vitro transfection study indicated that PCFC-g-PEI copolymer prepared in this paper was a novel gene delivery system with lower cytotoxicity and considerable transfection efficiency compared with commercial PEI (25 kD).

Transdermal anaesthesia with lidocaine nano-formulation pretreated with low-frequency ultrasound in rats model.

Rapid local transdermal anaesthetic is desirable in clinic. In this paper, lidocaine loaded poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) (PCL-PEG-PCL) nanoparticles were prepared, and a novel transdermal lidocaine formulation: lidocaine loaded PCL-PEG-PCL nanoparticles in F127 hydrogel (Nano-Lido Gel), was demonstrated. These lidocaine loaded PCL-PEG-PCL nanoparticles with mean particle size of ca. 200 nm had drug loading of about 40%. The efficiency of transdermal anaesthesia of four treatments: EMLA cream (E), Nano-Lido Gel (N), EMLA cream with brief focal ultrasound pretreatment (EU), and Nano-Lidocaine Gel with brief focal ultrasound pretreatment (NU), was evaluated by tail-flick latency test assay in rats. Results indicated that the topical anaesthesia onset time in NU was 5 times and 2.5 times shorter than that in E and EU. The efficiency of anaesthesia in NU, expressed as maximum possible effects (MPE) value, was significantly higher than that in other treatments. It provided a novel path to develop rapid transdermal anaesthesia by combination of ultrasound pretreatment and lidocaine nano-formulation based on polymeric nanoparticles.

Preparation and characterization of vitamin-12 loaded biodegradable pH-sensitive microgels.

This paper prepared novel biodegradable and pH-sensitive microgels based on Poly(epsilon-caprolactone)-Pluronic-Poly(epsilon-caprolactone)-dimethacrylate (PCFC-DMA), Poly(ethylene glycol) dimethacrylate (PEG-DMA) and methylacrylic acid (MAA) cross-linked with N,N'-methylenebisacrylamide (BIS), initiated by NaHSO(3), K(2)S(2)O(8). The blank microgels were prepared by inversed-phase suspension polymerization method and pH sensitivity of microgels was characterized. Then the blank microgels were loaded with hydrophilic model drug vitamin-12 (VB-12) and in vitro drug release behaviour was also studied here.

Doxorubicin-Conjugated Heparin-Coated Superparamagnetic Iron Oxide Nanoparticles for Combined Anticancer Drug Delivery and Magnetic Resonance Imaging.

In this study, superparamagnetic iron oxide (SPIO) nanoparticles (NPs) with an average size of 10±2 nm were coated with doxorubicin (Dox)-conjugated heparin (DH-SPIO) and were used for targeted anticancer drug delivery, and as a magnetic resonance imaging (MRI) contrast agent. The DH-SPIO NPs had a mean particle size of 125±10 nm and a zeta potential of ­35±3 mV. Fourier transform-infrared spectroscopy, X-ray diffraction spectroscopy, transmission electron microscopy, vibrating sample magnetometry, and MTT assay were used to investigate the properties of DH-SPIO NPs. The internalization of DH-SPIO NPs into A549 tumor cells was examined using fluorescence microscopy and quantified by flow cytometry. Prussian blue staining, total iron assay, in vitro MRI and transmission electron microscopy showed that DH-SPIO NPs had high superparamagnetic clustering effect. In vivo therapy of A549 human lung carcinoma, DHSPIO NPs displayed a higher efficacy than Dox in inhibiting tumor growth and prolonging the survival of mice bearing tumors. Meanwhile, the pathological damage to the cardiac tissue in mice treated with DH-SPIO NPs was significantly less severe than that of mice treated with free Dox at the same dosage. These results show that DH-SPIO NPs are promising biomaterials for combined drug therapy and clinical imaging.

A novel gene delivery composite system based on biodegradable folate-poly (ester amine) polymer and thermosensitive hydrogel for sustained gene release.

Local anti-oncogene delivery providing high local concentration of gene, increasing antitumor effect and decreasing systemic side effects is currently attracting interest in cancer therapy. In this paper, a novel local sustained anti-oncogene delivery system, PECE thermoresponsive hydrogel containing folate-poly (ester amine) (FA-PEA) polymer/DNA (tumor suppressor) complexes, is demonstrated. First, a tumor-targeted biodegradable folate-poly (ester amine) (FA-PEA) polymer based on low-molecular-weight polyethyleneimine (PEI) was synthesized and characterized, and the application for targeted gene delivery was investigated. The polymer had slight cytotoxicity and high transfection efficiency in vitro compared with PEI 25k, which indicated that FA-PEA was a potential vector for targeted gene delivery. Meanwhile, we successfully prepared a thermoresponsive PECE hydrogel composite containing FA-PEA/DNA complexes which could contain the genes and slowly release the genes into cells. We concluded the folate-poly (ester amine) (FA-PEA) polymer would be useful for targeted gene delivery, and the novel gene delivery composite based on biodegradable folate-poly (ester amine) polymer and thermosensitive PECE hydrogel showed potential for sustained gene release.

Self-assembled mPEG-PCL-g-PEI micelles for multifunctional nanoprobes of doxorubicin delivery and magnetic resonance imaging and optical imaging.

In this paper, a novel bifunctional nanoprobe based on polyethylene glycol(MPEG)-poly(ϵ-caprolactone)(ϵ-CL)-polyethylenimine(PEI) labeled with FITC (MPEG-PCL-PEI-FITC, PCIF) were prepared to provide tumor therapy and simultaneous diagnostic information via magnetic resonance imaging (MRI) and optical imaging. Superparamagnetic iron oxide (SPIO) and doxorubicin (DOX) loaded PCIF (PCIF/SPIO/DOX) nanoprobes were prepared by self-assembling into micelles, which had uniformly distributed particle size of 130 ± 5 nm and a zeta potential of +35 ± 2 mV. Transmission electronic microscopy(TEM) showed that SPIO NPs were loaded into PCIF micelles. The PCIF/SPIO/DOX nanoprobes were superparamagnetic at 300 K with saturated magnetization of 20.5 emu/g Fe by vibrating-sample-magnetomete (VSM). Studies on cellular uptake of PCIF/SPIO/DOX nanoprobes demonstrated that SPIO NPs, DOX and FITC labeled MPEG-PCL-PEI were simultaneously taken up by the breast cancer (4T1) cells. After intravenous injection of PCIF/SPIO/DOX nanoprobes in 4T1 tumor-bearing mice, SPIO NPs, DOX and FITC labeled MPEG-PCL-PEI micelles were simultaneously delivered into tumor tissue by histochemisty. This work is important for the applications to multimodal diagnostic and theragnosis as nanomedicine.

Preparation of curcumin-loaded poly(ester amine) nanoparticles for the treatment of anti-angiogenesis.

The aim of this study was to prepare curcumin loaded poly(ester amine) nanoparticles and enhance their hydrophilicity and treatment efficacy on anti-angiogenesis zebra fish model. Poly(ester amine) (PEA) copolymer was synthesized in this study. The curcumin-loaded PEA nanoparticles were prepared through double emulsion-solvent evaporation technique. The average particle size of obtained nanoparticles was about 100 nm. The zeta potential of prepared nanoparticles was about 35.8+/-2.4 mV. Transmission electron microscopy demonstrated a narrow size distribution with in vitro release profile demonstrating in vitro slow release of curcumin from the PEA nanoparticles. The in vitro cytotoxicity of the curcumin encapsulated PEA nanoparticles nearly had the same tendency of cytotoxic activity in vitro with free curcumin on tumor cells. In vitro cellular uptake of the curcumin-loaded nanoparticles demonstrated in Hela cells demonstrated that this kind of nanoparticles can be a promising candidate as a drug delivery system to cancer cells. The Cur/PEA nanoparticles more efficiently inhibited angiogenesis (in vivo) in transgenic zebra fish model and Alginate-encapsulated tumor cells than free curcumin. No mortality or significant lesions were observed from histopathological study of the major organs. From our results, we can conclude that the prepared PEA nanoparticles are an efficient curcumin drug delivery system for anti-angiogenesis therapy.

Preparation and in vitro characterization of dexamethasone-loaded poly(D,L-lactic acid) microspheres embedded in poly(ethylene glycol)-poly({varepsilon}-caprolactone)-poly(ethylene glycol) hydrogel for orthopedic tissue engineering.

The corium is decreased to about half of its thickness in skin defects and wrinkles due to gravity and environment. In this study, dexamethasone/poly(d,l-lactic acid) (Mn = 160,000) microspheres were incorporated into poly(ethylene glycol)-poly(ε-caprolactone)-poly(ethylene glycol) (Mn = 3300) hydrogel to prepare an injectable hydrogel composite. The composite was designed to increase the thickness of the corium. Dexamethasone/poly(d,l-lactic acid) microspheres were prepared by oil-in-water emulsion/solvent evaporation technique. The properties of microspheres were investigated by size distribution measurement, scanning electron microscope and x-ray diffraction. Drug loading, encapsulation efficiency, and drug delivery behavior of microspheres were also studied in detail. Cell adhesion of microspheres was investigated by NIH3T3 cell in vitro. The properties of hydrogel composite were investigated by scanning electron microscope, rheological measurements and methyl thiazolyl tetrazolium assay. Drug release from composite was determined by HPLC-UV analysis. These results suggested that poly(d,l-lactic acid) microspheres encapsulating dexamethasone embedded in poly(ethylene glycol)-poly(ε-caprolactone)-poly(ethylene glycol) hydrogel might have prospective application in orthopedic tissue engineering field.

Preparation and characterization of poly(pluronic-co-L-lactide) nanofibers for tissue engineering.

In this work, a new kind of biodegradable poly(pluronic-co-L-lactide) (Pluronic-PLLA copolymers) was successfully prepared by melt-polycondensation method from L-lactide, Pluronic and isophorone diisocyanate (IPDI). The obtained copolymers were characterized by (1)H NMR, FT-IR, X-ray, and TGA/DTA. Meanwhile, three-dimensional (3-D) porous scaffolds based on Pluronic-PLLA were prepared by the electrospinning method, the factors of concentration, flow rate and voltage that influence the formation of the Pluronic-PLLA nanofibers were studied and the structure of Pluronic-PLLA nanofibers were investigated by scanning electron microscopy (SEM). MTT results revealed that the Pluronic-PLLA scaffolds had good biocompatibility and nontoxicity. Morphological study using fluorescence micrographs and scanning electron microscopy showed that in vitro osteoblast cell culture demonstrated the electrospun Pluronic-PLLA composite scaffolds could provide a suitable environment for good cell attachment. These results suggested that such Pluronic-PLLA nanofibers membranes might have prospective applications in tissue engineering field.

PLA/PEG-PPG-PEG/dexamethasone implant prepared by hot-melt extrusion for controlled release of immunosuppressive drug to implantable medical devices, Part 2: in vivo evaluation.

Hot-melt extrusion (HME) plays an important role in preparing implants as local drug delivery systems in pharmaceutical fields. Here, a new PLA/PEG-PPG-PEG/Dexamethasone (PLA/F68/Dex) implant prepared by HME has been developed. Importantly, the implant was successfully achieved to control release of immunosuppressive drug to an implanted device. In particular, this implant has not been reported previously in pharmaceutical fields. FTIR and XRD were adopted to investigate the properties of the samples. The in vivo release study showed that the maximum value of Dex release from the implants was approximately 50% at 1 month. The in vivo degradation behavior was determined by UV spectrophotometer and scanning electron microscopy studies, and the weight loss rate of the implants were up to 25% at 1 month. Furthermore, complete blood count (CBC) test, serum chemistry and major organs were performed, and there is no significant lesion and side effects observed in these results. Therefore, the results elucidated that the new PLA/F68/Dex implant prepared by HME could deliver an immunosuppressive drug to control the inflammatory reaction at the implant site.

Self-assembled mPEG-PCL-g-PEI micelles for simultaneous codelivery of chemotherapeutic drugs and DNA: synthesis and characterization in vitro.

BACKGROUND: In this paper, a series of amphiphilic triblock copolymers based on polyethylene glycol-poly ɛ-caprolactone-polyethylenimine (mPEG-PCL-g-PEI) were successfully synthesized, and their application for codelivery of chemotherapeutic drugs and DNA simultaneously was investigated. METHODS AND RESULTS: These copolymers could self-assemble into micelles with positive charges. The size and zeta potential of the micelles was measured, and the results indicate that temperature had a large effect on the micelles obtained. In vitro gene transfection evaluation in cancer cells indicated that the self-assembled micelles could serve as potential gene delivery vectors. In addition, hydrophobic drug entrapment efficiency and codelivery with the gene was also studied in vitro. The self-assembled micelles could load doxorubicin efficiently and increase cellular uptake in vitro, while maintaining high gene transfection efficiency. CONCLUSION: The triblock copolymer mPEG-PCL-g-PEI could be a novel vector for codelivery of drug and gene therapy.

Enhanced gene delivery using biodegradable poly(ester amine)s (PEAs) based on low-molecular-weight polyethylenimine and poly(epsilon-caprolactone)-pluronic-poly(epsilon-caprolactone).

In this paper, the poly(ester amine)s (PEAs) were successfully prepared from low-molecular-weight PEI (Mn = 2000) and Poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol)-poly(epsilon-caprolactone) (PCFC) copolymers using isophorone diisocyanate (IPDI) as cross-linker. The obtained PEAs copolymers are biodegradable and water-soluble. The PEAs/DNA complexes showed effective and stable DNA condensation with the particle size < or = 200 nm and zeta potential > or =10 mV, indicating its potential for intracellular delivery. Compared to the unmodified low-molecular-weight PEI, PEAs displayed similarly low cytotoxicity in all two cell lines (293T: Human kidney carcinoma, HUVEC: Human umbilical vein Endothelial cell) and revealed much higher transfection efficiency in 293T cell lines. Therefore these PEAs might be a novel safe and efficient polymeric gene delivery vectors.

Preparation of honokiol-loaded chitosan microparticles via spray-drying method intended for pulmonary delivery.

It has been demonstrated that spray-drying is a powerful method to prepare dry powders for pulmonary delivery. This paper prepared dispersible dry powders based on chitosan and mannitol containing honokiol nanoparticles as model drug. The results showed that the prepared microparticles are almost spherical and have appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters was between 2.8-3.3 microm and tapped density ranging from 0.14-0. 18 g/cm(3)). Moreover, surface morphology and aerodynamic properties of the powders were strongly affected by the content of mannitol. Fourier transform infra-red (FTIR) spectrum of powders indicated that the honokiol nanoparticles were successfully incorporated into microparticles. In vitro drug release profile was also observed. The content of mannitol in powders significantly influenced the release rate of honokiol from matrices.

Biodegradable in situ gel-forming controlled drug delivery system based on thermosensitive PCL-PEG-PCL hydrogel. Part 2: sol-gel-sol transition and drug delivery behavior.

In this work, a biodegradable and injectable in situ gel-forming controlled drug delivery system based on thermosensitive poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) (PCEC) hydrogel was studied. The prepared PCEC hydrogel undergoes temperature-dependent sol-gel-sol transition, which is a flowing sol at ambient temperature and turns into a non-flowing gel at around physiological body temperature. Furthermore, the sol-gel phase transition mechanism was investigated using (13)C-nuclear magnetic resonance imaging and a laser diffraction particle size analyzer. The in vitro release behaviors of several model drugs, including a hydrophilic small-molecule drug, a hydrophobic small-molecule drug and a macromolecular protein drug, from PCEC hydrogel were also investigated in detail. The results showed that the model drugs could be released from the PCEC hydrogel system over a sustained period. In addition, an anaesthesia assay was conducted using the tail flick latency (TFL) test to evaluate the in vivo controlled drug delivery effect of the PCEC hydrogel system. In the TFL assay, a lidocaine-loaded PCEC hydrogel produced significantly longer-lasting local anaesthetic effects compared with lidocaine aqueous solution at the same dose. Therefore, PCEC hydrogel is promising for use as an injectable local drug delivery system.