Self-assembled pH-responsive polymeric nanoparticles based on lignin-histidine conjugate with small particle size for efficient delivery of anti-tumor drugs

Peptide-based nanomaterials and their diverse applications

The supramolecular self-assembly of peptides offers a promising avenue for both materials science and biological applications. Peptides have garnered significant attention in molecular self-assembly, forming diverse nanostructures with α-helix, β-sheet, and random coil conformations. These self-assembly processes are primarily driven by the amphiphilic nature of peptides and stabilized by non-covalent interactions, leading to complex nanoarchitectures responsive to environmental stimuli. While extensively studied in biomedical applications, including drug delivery and tissue engineering, their potential applications in the fields of piezoresponsive materials, conducting materials, catalysis and energy harvesting remain underexplored. This review comprehensively elucidates the diverse material characteristics and applications of self-assembled peptides. We discuss the multi-stimuli-responsiveness of peptide self-assemblies and their roles as energy harvesters, catalysts, liquid crystalline materials, glass materials and contributors to electrical conductivity. Additionally, we address the challenges and present future perspectives associated with peptide nanomaterials. This review aims to provide insights into the versatile applications of peptide self-assemblies while concisely summarizing their well-established biomedical roles that have previously been extensively reviewed by various research groups, including our group.

Biomass-Derived Organonanomaterials as Contrast Agents for Efficient Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is a popular imaging tool that is valuable for the early detection and monitoring of malignancies because it does not involve radiation and is noninvasive. Metal-based contrast agents (CAs) are commonly used in clinical settings despite concerns about the toxicity of free metals. Therefore, finding alternative nontoxic imaging probes is vital. In this work, we have synthesized and effectively utilized sustainable biomass lignin-based all-organic nanoconjugates linked with nitroxide radicals as MRI CAs. Lignin grafted with poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (LPGT) exhibits a longitudinal relaxivity of 0.54 mM-1 s-1. LPGT shows exceptional characteristics, including resistance to reduction and nontoxicity toward living organisms. LPGT displays enhanced MRI contrast in the BALB/c mouse model for a duration exceeding 4.35 h. Our primary goal is to design MRI agents that are exceptionally effective sustainable biomass-derived materials and do not require the use of metals. Nicely, LPGT offers adequate contrast enhancement at 5-fold lower (0.020 mmol/kg) than the standard dose (0.1 mmol/kg), easing worries about toxic metal buildup. Consequently, LPGT shows promise as a feasible CA for metal-free MRI.

Exploiting lignin-based nanomaterials for enhanced anticancer therapy: A comprehensive review and future direction

Lignin, a renewable and abundant natural polymer, has emerged as a promising candidate for anticancer therapy due to its unique properties and biocompatibility. This review provides a comprehensive overview of recent advancements in the utilization of lignin-based nanomaterials for enhancing anticancer drug delivery and therapeutic outcomes. A detailed examination of the literature reveals several synthesis methods, including nanoprecipitation, microemulsion, and solvent exchange, which produce lignin nanoparticles with improved drug solubility and bioavailability. The anticancer mechanisms of lignin nanoparticles, such as the generation of reactive oxygen species (ROS), induction of apoptosis, and enhanced cellular uptake, are also explored. Lignin nanoparticles loaded with drugs like curcumin, doxorubicin, camptothecin, and resveratrol have demonstrated the ability to improve drug efficacy, selectively target cancer cells, overcome multidrug resistance, and minimize toxicity in both in vitro and in vivo studies. These nanoparticles have shown significant potential in suppressing tumor growth, inducing cell death through apoptotic pathways, and enhancing the synergistic effects of combination therapies, such as chemo-phototherapy. Future research directions include optimizing lignin nanoparticle formulations for clinical applications, refining targeted delivery mechanisms to cancer cells, and conducting thorough biocompatibility and toxicity assessments. Overall, this review highlights the significant progress made in utilizing lignin-based nanomaterials for cancer therapy and outlines promising areas for further exploration in this rapidly evolving field.

pH-responsive magnetic CuFe2O4-PMAA nanogel conjugated with amino-modified lignin for controlled breast cancer drug delivery

In this study, a novel magnetic and pH-responsive nanocarrier was developed, incorporating both natural and synthetic polymers, for delivering curcumin (CUR) to breast cancer cells. For this purpose, CuFe2O4@poly(methacrylic acid) (CuFe2O4@PMAA) nanogel was developed and conjugated with amino-modified lignin (Lignin-adipic acid dihydrazide conjugate, Lig-ADH) to achieve the CuFe2O4@PMAA@Lig-ADH nanocarrier. The morphology, structure, and physical properties of the synthesized nanomaterials were examined using a range of techniques, including transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX), and vibrating sample magnetometer (VSM). The synthesized nanocarrier exhibited a spherical shape, with an average diameter of approximately 15 nm, and demonstrated good magnetic responsiveness. Moreover, the in vitro drug release was found to be pH-dependent, with an increased release rate in acidic conditions. To evaluate cytotoxicity, the survival of MCF-7 cells was measured using the MTT assay for 24 h. Notably, the synthesized CuFe2O4@PMAA@Lig-ADH@CUR and CUR exhibited significant cytotoxic effects, effectively eliminating MCF-7 cells with IC50 values of 39.80 µg/mL and 4.27 µg/mL, respectively. Also, the significant intracellular uptake of NPs was confirmed by FITC and DAPI staining after 4 h. This research highlighted the potential of CuFe2O4@PMAA@Lig-ADH@CUR as a highly effective nano-delivery system and demonstrated a straightforward method for utilizing renewable lignin.

Lignin-Based Nanoparticles for Combination of Tumor Oxidative Stress Amplification and Reactive Oxygen Species Responsive Drug Release

In this study, maleic anhydride-modified lignin (LG-M), a ROS-cleavable thioketal (TK) bond, and polyethylene glycol (PEG) were used to synthesize a lignin-based copolymer (LG-M(TK)-PEG). Doxorubicin (DOX) was attached to the ROS-cleavable bond in the LG-M(TK)-PEG for the preparation of the ROS-activatable DOX prodrug (LG-M(TK-DOX)-PEG). Nanoparticles (NPs) with a size of 125.7 ± 3.1 nm were prepared by using LG-M(TK-DOX)-PEG, and they exhibited enhanced uptake by cancer cells compared to free DOX. Notably, the presence of lignin in the nanoparticles could boost ROS production in breast cancer 4T1 cells while showing little effect on L929 normal cells. This selective effect facilitated the specific activation of the DOX prodrug in the tumor microenvironment, resulting in the superior tumor inhibitory effects and enhanced biosafety relative to free DOX. This work demonstrates the potential of the LG-M(TK-DOX)-PEG NPs as an efficient drug delivery system for cancer treatment.

Doxorubicin encapsulated blend of sitagliptin-lignin polymeric drug delivery system for effective combination therapy against cancer

In this research, a sitagliptin-lignin biopolymer (SL) containing zinc selenide quantum dots (ZnSe QDs) and doxorubicin (doxo) was synthesized. The fabricated polymeric drug delivery system was characterized via FTIR, XRD, SEM, TGA, IR, and DSC. SLQD-Doxo exhibited an irregular surface with a 32 nm diameter and well-defined surface chemistry. Drug loading efficiency was assessed at different concentrations, pH levels, time intervals, and temperatures, and drug kinetics were calculated. Maximum drug release was observed at 6 μmol concentration after 24 h, pH of 6.5 and 45 °C. The maximum drug encapsulation efficiency was 81.75 %. SLQD-Doxo demonstrated 24.4 ± 1.04 % anti-inflammatory activity, and the maximum lipoxygenase inhibition in a concentration-dependent manner was 71.45 ± 2.02 %, compared to indomethacin, a standard anticancer drug. The designed system was applied to breast cancer MCF-7 cells to evaluate anticancer activity. Cytotoxicity of SLQD-Doxo resulted in 24.48 ± 1.64 dead cells and 74.39 ± 4.12 viable cells. Lignin's polyphenolic nature resulted in good antioxidant activity of LLQD-Doxo. The combination of SLQD-Doxo was appropriate for drug delivery at high temperatures and acidic pH of tumor cells compared to healthy cells.

Lignocellulosic-biomolecules conjugated systems: green-engineered complexes modified by covalent linkers

Lignocellulosic biomass represents an abundant and eco-friendly material widely explored in recent years. The main lignocellulosic fractions include cellulose, hemicellulose, and lignin. Nonetheless, the heterogeneity and complexity of these components pose challenges in achieving the desired properties. Conversely, their attractive functional groups can covalently link with other biomolecules, facilitating the creation and enhancement of material properties. Lignocellulosic molecules can form different linkages with other biomolecules through classic and modern methods. Bioconjugation has emerged as a suitable alternative to create new nuances, empowering the linkage between lignocellulosic materials and biomolecules through linkers. These conjugates (lignocellulosic-linkers-biomolecules) attract attention from stakeholders in medicine, chemistry, biology, and agriculture. The plural formations of these biocomplexes highlight the significance of these arrangements. Therefore, this review provides an overview of the progress of lignocellulosic-biomolecule complexes and discusses different types of covalent bioconjugated systems, considering the formation of linkers, applicability, toxicity, and future challenges.

Synthesis, characterization and application of emamectin-alkaline lignin conjugate with photolysis resistance and systemic translocation

Controlled release formulations (CRFs) are a key technical approach for the sustainable development of pesticides. In this study, a CRF conjugate (emamectin-alkaline lignin, EB-AL) was successfully prepared using alkaline lignin as the substrate, with amide bond connecting emamectin and alkaline lignin. The structure and morphology of the conjugate were characterized using IR, ¹HNMR, elemental analysis, SEM and TG. The release of EB-AL showed that the conjugate maintained its original structure when released in 50 % methanol-water and soil column, and the amide bond remained intact. The anti-photolysis test revealed that EB-AL had a 3.5 times higher photolysis half-life T_0.5 than the general emamectin suspension concentrate (EB-SC). Bioactivity tests in the greenhouse demonstrated that EB-AL possessed a longer insecticidal duration and good biosafety. Ostrinia nubilalis lethality rate remained above 70 % for 19 days, while EB-EC, the control, had a rate of <50 % after 11 days of application. Additionally, EB-AL conjugate demonstrated excellent systemic translocation in plants, likely due to its ability to mediate alkaline lignin.

Stabilized Lignin Nanoparticles for Versatile Hybrid and Functional Nanomaterials

Spherical lignin nanoparticles are emerging biobased nanomaterials, but instability and dissolution in organic solvents and aqueous alkali restrict their applicability. Here, we report the synthesis of hydroxymethylated lignin nanoparticles and their hydrothermal curing to stabilize the particles by internal cross-linking reactions. These colloidally stable particles contain a high biobased content of 97% with a tunable particle size distribution and structural stability in aqueous media (pH 3 to 12) and organic solvents such as acetone, ethanol, dimethylformamide, and tetrahydrofuran. We demonstrate that the free phenolic hydroxyl groups that are preserved in the cured particles function as efficient reducing sites for silver ions, giving rise to hybrid lignin-silver nanoparticles that can be used for quick and facile sensing of hydrogen peroxide. The stabilized lignin particles can also be directly modified using base-catalyzed reactions such as the ring-opening of cationic epoxides that render the particles with pH-dependent agglomeration and redispersion properties. Combining scalable synthesis, solvent stability, and reusability, this new class of lignin nanoparticles shows potential for its use in circular biobased nanomaterials.

Responsive Peptide Nanofibers with Theranostic and Prognostic Capacity

Photodynamic therapy (PDT) is a highly promising therapeutic modality for cancer treatment. The development of stimuli-responsive photosensitizer nanomaterials overcomes certain limitations in clinical PDT. Herein, we report the rational design of a highly sensitive PEGylated photosensitizer-peptide nanofiber (termed PHHPEG6 NF) that selectively aggregates in the acidic tumor and lysosomal microenvironment. These nanofibers exhibit acid-induced enhanced singlet oxygen generation, cellular uptake, and PDT efficacy in vitro, as well as fast tumor accumulation, long-term tumor imaging capacity and effective PDT in vivo. Moreover, based on the prolonged presence of the fluorescent signal at the tumor site, we demonstrate that PHHPEG6 NFs can also be applied for prognostic monitoring of the efficacy of PDT in vivo, which would potentially guide cancer treatment. Therefore, these multifunctional PHHPEG6 NFs allow control over the entire PDT process, from visualization of photosensitizer accumulation, via actual PDT to the assessment of the efficacy of the treatment.

Role of lignin-based nanoparticles in anticancer drug delivery and bioimaging: An up-to-date review

Lignin, an aromatic biopolymer, is the second most abundant naturally occurring one after cellulose that has drawn a great deal of interest over the years for its potential uses owing to the presence of high content of phenolic compounds, ecofriendly feature and cost-efficiency in comparison to the synthetic polymers. Nevertheless, with the intention of advancing its development, several efforts have been performed in the direction of utilizing lignin on the nanoscale due to its inimitable properties. The notable absorption capacity, fluorescence emission, biodegradability and non-toxicity of lignin nanoparticles permit its appropriateness as a vehicle for drugs and as a bioimaging material. Moreover, lignin nanoparticles have shown plausible therapeutic effects, such as anticancer, antimicrobial, and antioxidant. The current review sheds light on the recent development in the formulation and anticancer applications of lignin nanoparticles as a drug carrier and as a diagnostic tool. The surface properties of the nanomaterial affect the end product characteristics, hence, factors namely; lignin source, isolation technique, purification and quantitation methods, are discussed in this review. This study represents original work that has not been published elsewhere and that has not been submitted simultaneously for publication elsewhere. The manuscript has been read, revised, and approved by the authors.

Preparation and Insecticidal Activity Evaluation of Emamectin-Lignin Sulfonic Acid Conjugate with Antiphotolysis Property

Controlled release formulations (CRFs) are considered an effective way to solve the low bioavailability of traditional pesticides. However, CRFs prepared by coating or encapsulation has the disadvantage of explosive release of the ingredients. Sustained-release pesticides prepared by coupling with a carrier can overcome this shortcoming. In the present study, an emamectin-lignin sulfonic acid conjugate (EB-SL), in which emamectin was connected via sulfonamide bonds with lignin, was prepared using sodium lignosulfonate as the carrier. The structure of the conjugate was characterized by IR, ¹HNMR, and elemental analysis. The sustained-release results showed that EB-SL maintained its original structure when released in pure water and soil columns, and the sulfamide bond did not break. The photolysis test displayed that the photolysis half-life T _0.5 of EB-SL was increased by 1.5 times compared with the emamectin suspending concentrate (EB-SC). Bioactivity tests in the greenhouse showed that EB-SL not only had similar insecticidal toxicity to emamectin emulsion concentrate (EB-EC) against Ostrinia nubilalis but also displayed a longer duration. The lethality of EB-SL on O. nubilalis was maintained at more than 70% across 19 days, whereas EB-EC as the control was less than 50% after 11 days of application.

Lignin as a Natural Carrier for the Efficient Delivery of Bioactive Compounds: From Waste to Health

Lignin is a fascinating aromatic biopolymer with high valorization potentiality. Besides its extensive value in the biorefinery context, as a renewable source of aromatics lignin is currently under evaluation for its huge potential in biomedical applications. Besides the specific antioxidant and antimicrobial activities of lignin, that depend on its source and isolation procedure, remarkable progress has been made, over the last five years, in the isolation, functionalization and modification of lignin and lignin-derived compounds to use as carriers for biologically active substances. The aim of this review is to summarize the current state of the art in the field of lignin-based carrier systems, highlighting the most important results. Furthermore, the possibilities and constraints related to the physico–chemical properties of the lignin source will be reviewed herein as well as the modifications and processing required to make lignin suitable for the loading and release of active compounds.

pH-Responsive Self-Assembling Peptide-Based Biomaterials: Designs and Applications

Stimuli-responsive peptide-based biomaterials are increasingly gaining interest for various specific and targeted treatments, including drug delivery and tissue engineering. Among all stimuli, pH can be especially useful because endogenous pH changes are often associated with abnormal microenvironments. pH-Responsive amino acids and organic linkers can be easily incorporated into peptides that self-assemble into various nanostructures. Thus, these largely biocompatible and easily tunable platforms are ideal candidates for drug release and as fibrous materials capable of mimicking the native extracellular matrix. In this review, we highlight common design motifs and mechanisms of pH-responsiveness in self-assembling peptide-based biomaterials, focusing on recent advances of these biomaterials applied in drug delivery and tissue engineering. Finally, we suggest future challenges and areas for potential development in pH-responsive self-assembling peptide-based biomaterials.

Current State-of-the-Art and New Trends in Self-Assembled Nanocarriers as Drug Delivery Systems

Self-assembled nanocarrier drug delivery has received profuse attention in the field of diagnosis and treatment of diseases. These carriers have proved that serious life-threatening diseases can be eliminated evidently by virtue of their characteristic design and features. This review is aimed at systematically presenting the research and advances in the field of self-assembled nanocarriers such as polymeric nanoparticles, dendrimers, liposomes, inorganic nanocarriers, solid lipid nanoparticles, polymerosomes, micellar systems, niosomes, and some other nanoparticles. The self-assembled delivery of nanocarriers has been developed in recent years for targeting diseases. Some of the innovative attempts with regard to prolonging drug action, improving bioavailability, avoiding drug resistance, enhancing cellular uptake, and so on have been discussed. The discussion about various delivery systems included the investigation conducted at the preliminary stage, i.e., preclinical trials and assessment of safety. The clinical studies of some of the recently developed self-assembled products are currently at the clinical trial phase or FDA approved.

Microfluidic Synthesis of Lignin/Chitosan Nanoparticles for the pH-Responsive Delivery of Anticancer Drugs

In this work, lignin/chitosan nanoparticles (Lig/Chi NPs) with controlled structures were synthesized in a simple and scalable microfluidic system. When the positively charged chitosan and the negatively charged lignin solution were blended in a microreactor, Lig/Chi NPs were rapidly formed via the electrostatic coassembly between the amino groups of chitosan and the carboxyl groups of lignin. The ζ potential changes from negative (-13 mV) to positive (+54.5 mV) for Lig NPs and Lig/Chi NPs, respectively. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results demonstrated that Lig/Chi NPs have an average particle size of about 180 nm, which can be used as nanocarriers for drug delivery. The anticancer drug nanoparticles with docetaxel (DTX) and curcumin (CCM) were prepared by coassembly with Lig/Chi NPs in a microreactor, which had good drug loading efficiency, biocompatibility, and can release drugs in response to pH in the weakly acidic environment of the tumor. The drug release amounts in acidic solutions that simulated the tumor microenvironment were 51% (DTX@Lig/Chi NPs) and 50% (CCM@Lig/Chi NPs), respectively, which were better than the release amounts at pH 7.4, and have an obvious killing effect on HeLa cells.

Photophysical and Antibacterial Properties of Porphyrins Encapsulated inside Acetylated Lignin Nanoparticles

Lignin has recently attracted the attention of the scientific community, as a suitable raw material for biomedical applications. In this work, acetylated lignin was used to encapsulate five different porphyrins, aiming to preserve their photophysical properties, and for further use as antibacterial treatment. The obtained nanoparticles were physically characterized, through dynamic light scattering size measurement, polydispersity index and zeta potential values. Additionally, the photophysical properties of the nanoparticles, namely UV-vis absorption, fluorescence emission, singlet oxygen production and photobleaching, were compared with those of the free porphyrins. It was found that all the porphyrins were susceptible to encapsulation, with an observed decrease in their fluorescence quantum yield and singlet oxygen production. These nanoparticles were able to exert an effective photodynamic bactericide effect (blue-LED light, 450-460 nm, 15 J/cm2) on Staphylococcus aureus and Escherichia coli. Furthermore, it was achieved a photodynamic bactericidal activity on an encapsulated lipophillic porphyrin, where the free porphyrin failed to diminish the bacterial survival. In this work it was demonstrated that acetylated lignin encapsulation works as a universal, cheap and green material for the delivery of porphyrins, while preserving their photophysical properties.

State-of-the-Art: Applications and Industrialization of Lignin Micro/Nano Particles

As a new product of high-value utilization of lignin, lignin micro/nano particles (LMNPs) have attracted the attention of researchers due to their non-toxicity, corrosion-resistance, UV resistance, and other excellent characteristics and potential application value. This article outlined the main preparation methods of LMNPs at the current stage, summarized and compared them from three perspectives of preparation technology, final product state and product composition. Subsequently, based on the different focuses of the properties of LMNPs, their application research progress as fillers, UV blockers, drug delivery carriers, among others, were introduced. Then a concise analysis of the technical and economic assessment and life cycle assessment of LMNPs in the process of industrialization was made. Finally, the main problems at present and the future development directions were analyzed and prospected to provide references for the deep processing of forest resources and the development of bio-based nanomaterials.

Advancement of nanoscience in development of conjugated drugs for enhanced disease prevention

Nanoscience and nanotechnology is a recently emerging and rapid developing field of science and has also been explored in the fields of Biotechnology and Medicine. Nanoparticles are being used as tools for diagnostic purposes and as a medium for the delivery of therapeutic agents to the specific targeted sites under controlled conditions. The physicochemical properties of these nanoparticles give them the ability to treat various chronic human diseases by site specific drug delivery and to use in diagnosis, biosensing and bioimaging devices, and implants. According to the type of materials used nanoparticles can be classified as organic (micelles, liposomes, nanogels and dendrimers) and inorganic (including gold nanoparticles (GNPs), super-paramagnetic iron oxide nanomaterials (SPIONs), quantum dots (QDs), and paramagnetic lanthanide ions). Different types of nanoparticle are being used in conjugation with various types of biomoities (such as peptide, lipids, antibodies, nucleotides, plasmids, ligands and polysaccharides) to form nanoparticle-drug conjugates which has enhanced capacity of drug delivery at targeted sites and hence improved disease treatment and diagnosis. In this study, the summary of various types of nanoparticle-drug conjugates that are being used along with their mechanism and applications are included. In addition, the various nanoparticle-drug conjugates which are being used and which are under clinical studies along with their future opportunities and challenges are also discussed in this review.

Quality by design (QbD) approach in processing polymeric nanoparticles loading anticancer drugs by high pressure homogenizer

Polymeric nanoparticles prepared using high pressure homogenizer (HPH) present some unique challenges during manufacturing which can be better understood by application of quality by design (QbD) approaches. The present review highlights the ways to identify the critical material attributes which includes the anticancer drugs, polymers, surfactants, solvent system and dispersion system. A comprehensive understanding of the critical processing parameters like pressure and number of cycles during the working of HPH used in putting forward the critical quality attributes such as size, shape, surface charge or droplet stabilization. Such QbD approach will involve development of an effective control strategy for would ensure safe encapsulation of anticancer drugs for successful product development. Proper addressing of the issues related to scaling-up would lead to successful commercialization of the nano-sized formulations loaded with anticancer drugs.