Fluorescence of tautomeric forms of curcumin in different pH and biosurfactant rhamnolipids systems: Application towards on-off ratiometric fluorescence temperature sensing

Smart nano-inks based on natural food colorant for screen-printing of dynamic shelf life of shrimp

Intelligent packaging embedded with food freshness indicators can monitor food quality and be deployed for food safety and cutting food waste. The innovative nano-inks for dynamic shelf-life printing based on natural food colorant with application in real-time monitoring of shrimp freshness were prepared. Co-assembly of saffron petal anthocyanin (SPA) with hydrophobic curcumin (Cur) into chitin nano-scaffold (particle sizes around 26 ± 8 nm) could deliver hindering SPA leaching, confirmed by FT-IR, FE-SEM, AFM, and color stability test. The best response to pH-sensitivity was found in a ratio of (1:4) Cur/SPA (30% (v/w) in ChNFs that was correlated with the chemical and microbial changes of shrimp during shrimp freshness. However, smart screen-printed inks signified higher responsiveness to pH changes than FFI films. Therefore, smart-printed indicators introduced the excellent potential for a short response time, easy, cost-effective, eco-friendly, co-assembly, great color stabilities, and lifetime for nondestructively freshness monitoring foods and supplements.

Enhancement of Solubility, Stability, Cellular Uptake, and Bioactivity of Curcumin by Polyvinyl Alcohol

The biological activities and related mechanisms of curcumin, a major polyphenolic compound in turmeric, the rhizome of Curcuma longa, have been extensively investigated. Due to its poor solubility in water, the analysis of curcumin's biological activities is limited in most aqueous experimental systems. In the present study, the effects of polyvinyl alcohol (PVA), a dietary-compatible vehicle, on the solubility, stability, cellular uptake, and bioactivities of curcumin were investigated. Curcumin solubility was improved significantly by PVA; the color intensity of curcumin aqueous solution in the presence of PVA increased concentration-dependently with its peak shift to a shorter wavelength. Improved suspension stability and photostability of curcumin in an aqueous solution were also observed in the presence of PVA, even at 62.5 μg/mL. The scavenging activities of curcumin against DPPH, ABTS, AAPH radicals, and nitric oxide were enhanced significantly in the presence of PVA. PVA at 250 μg/mL also significantly enhanced the cytotoxic activity of curcumin against both HCT 116 colon cancer and INT 407 (HeLa-derived) embryonic intestinal cells by reducing the IC50 from 16 to 11 μM and 25 to 15 μM, respectively. PVA improved the cellular uptake of curcumin in a concentration-dependent manner in INT 407 cells; it increased the cellular levels more effectively at lower curcumin treatment concentrations. The present results indicate that PVA improves the solubility and stability of curcumin, and changes in these chemical behaviors of curcumin in aqueous systems by PVA could enhance the bioavailability and pharmacological efficacy of curcumin.

Enhancing Curcumin's therapeutic potential in cancer treatment through ultrasound mediated liposomal delivery

Improving the efficacy of chemotherapy remains a key challenge in cancer treatment, considering the low bioavailability, high cytotoxicity, and undesirable side effects of some clinical drugs. Targeted delivery and sustained release of therapeutic drugs to cancer cells can reduce the whole-body cytotoxicity of the agent and deliver a safe localized treatment to the patient. There is growing interest in herbal drugs, such as curcumin, which is highly noted as a promising anti-tumor drug, considering its wide range of bioactivities and therapeutic properties against various tumors. Conversely, the clinical efficacy of curcumin is limited because of poor oral bioavailability, low water solubility, instability in gastrointestinal fluids, and unsuitable pH stability. Drug-delivery colloid vehicles like liposomes and nanoparticles combined with microbubbles and ultrasound-mediated sustained release are currently being explored as effective delivery modes in such cases. This study aimed to synthesize and study the properties of curcumin liposomes (CLs) and optimize the high-frequency ultrasound release and uptake by a human breast cancer cell line (HCC 1954) through in vitro studies of culture viability and cytotoxicity. CLs were effectively prepared with particles sized at 81 ± 2 nm, demonstrating stability and controlled release of curcumin under ultrasound exposure. In vitro studies using HCC1954 cells, the combination of CLs, ultrasound, and Definity microbubbles significantly improved curcumin's anti-tumor effects, particularly under specific conditions: 15 s of continuous ultrasound at 0.12 W/cm2 power density with 0.6 × 107 microbubbles/mL. Furthermore, the study delved into curcumin liposomes' cytotoxic effects using an Annexin V/PI-based apoptosis assay. The treatment with CLs, particularly in conjunction with ultrasound and microbubbles, amplified cell apoptosis, mainly in the late apoptosis stage, which was attributed to heightened cellular uptake within cancer cells.

Self-emulsifying drug delivery systems (SEDDS): How organic solvent release governs the fate of their cargo

Organic solvents are commonly used in self-emulsifying drug delivery systems (SEDDS) to increase payloads of orally administered poorly soluble drugs. Since such solvents are released to a varying extent after emulsification, depending on their hydrophilic nature, they have a substantial impact on the cargo. To investigate this impact in detail, quercetin and curcumin as model drugs were incorporated in SEDDS comprising organic solvents (SEDDS-solvent) of logP < 2 and > 2. SEDDS were characterized regarding size, payload, emulsification time and solvent release. The effect of solvent release on the solubility of these drugs was determined. Preconcentrates of SEDDS-solventlogP < 2 emulsified more rapidly (< 1.5 min) forming smaller droplets than SEDDS-solventlogP > 2. Although, SEDDS-solventlogP < 2 preconcentrates provided higher quercetin solubility than the latter, a more pronounced solvent release caused a more rapid quercetin precipitation after emulsification (1.5 versus 4 h). In contrast, the more lipophilic curcumin was not affected by solvent release at all. Particularly, SEDDS-solventlogP < 2 preconcentrates provided high drug payloads without showing precipitation after emulsification. According to these results, the fate of moderate lipophilic drugs such as quercetin is governed by the release of solvent, whereas more lipophilic drugs such as curcumin remain inside the oily phase of SEDDS even when the solvent is released.

Unravel the Tangle: Atomistic Insight into Ultrahigh Curcumin-Loaded Polymer Micelles

Amphiphilic ABA-triblock copolymers, comprised of poly(2-oxazoline) and poly(2-oxazine), can solubilize poorly water-soluble molecules in a structure-dependent manner forming micelles with exceptionally high drug loading. All-atom molecular dynamics simulations are conducted on previously experimentally characterized, curcumin-loaded micelles to dissect the structure-property relationships. Polymer-drug interactions for different levels of drug loading and variation in polymer structures of both the inner hydrophobic core and outer hydrophilic shell are investigated. In silico, the system with the highest experimental loading capacity shows the highest number of drug molecules encapsulated by the core. Furthermore, in systems with lower loading capacity outer A blocks show a greater extent of entanglement with the inner B blocks. Hydrogen bond analyses corroborate previous hypotheses: poly(2-butyl-2-oxazoline) B blocks, found experimentally to have reduced loading capacity for curcumin compared to poly(2-propyl-2-oxazine), establish fewer but longer-lasting hydrogen bonds. This possibly results from different sidechain conformations around the hydrophobic cargo, which is investigated by unsupervised machine learning to cluster monomers in smaller model systems mimicking different micelle compartments. Exchanging poly(2-methyl-2-oxazoline) with poly(2-ethyl-2-oxazoline) leads to increased drug interactions and reduced corona hydration; this suggests an impairment of micelle solubility or colloidal stability. These observations can help driving forward a more rational a priori nanoformulation design.

Surface stabilization determines macrophage uptake, cytotoxicity, and bioactivity of curcumin nanocrystals

Pharmaceutical nanocrystals represent a promising new formulation that combines the benefits of bulk crystalline materials and colloidal nanoparticles. To be applied in vivo, nanocrystals must meet several criteria, namely colloidal stability in physiological media, non-toxicity to healthy cells, avoidance of macrophage clearance, and bioactivity in the target tissue. In the present work curcumin, a naturally occurring poorly water-soluble molecule with a broad spectrum of bioactivity has been considered as a candidate substance for preparing pharmaceutical nanocrystals. Curcumin nanocrystals in the size range of 40-90 nm were prepared by wet milling using the following combination of steric and ionic stabilizers: Tween 80, sodium dodecyl sulfate, Poloxamer 188, hydroxypropyl methylcellulose, phospholipids (with and without polyethylene glycol), and their combination. Nanocrystals stabilized by a combination of phospholipids enriched with polyethylene glycol proved to be the most successful in all evaluated criteria; they were colloidally stable in all media, exhibited low macrophage clearance, and proved non-toxic to healthy cells. This curcumin nanoformulation also exhibited outstanding anticancer potential comparable to commercially used cytostatics (IC₅₀=73 µM; 24 h, HT-29 colorectal carcinoma cell line) which represents an improvement of several orders of magnitude when compared to previously studied curcumin formulations. This work shows that the preparation of phospholipid-stabilized nanocrystals allows for the conversion of poorly soluble compounds into a highly effective "solution-like" drug delivery system at pharmaceutically relevant drug concentrations.

Click synthesis of novel dendronized curcumin and analogs. Strengthening of physicochemical properties toward biological applications

Curcumin and its analogs, chalcones, and C5-monocarbonyl are molecules of great therapeutic potential, but their poor stability and hydrophobicity have hampered their extensive use in clinical trials. Therefore, significant efforts have been made in materials science to improve their physicochemical properties. In this study, we propose dendronization as a synthetic strategy to strengthen some physicochemical properties such as solubility and stability of curcumin and analogs, taking advantage of the click chemistry (CuAAC) to attach second-generation polyester dendrons to the unsaturated cores. The dendronization, with the subsequent formation of aromatic triazole groups as linkers, not only modified the solubility and stability of the molecular systems but also favored the diketo tautomeric form of curcumin, as demonstrated spectroscopically. This result is significant since the diketo tautomer, which preserves the antioxidant properties of curcumin, is the most biologically active form. The hydrophobic/hydrophilic balance, achieved after dendronization, allowed the solubilization of the chromophoric molecules in buffered solutions at relevant pH values (7.4 and 6.4). Furthermore, the stability of all molecules was also upgraded since UV-vis absorption spectra did not exhibit modified profiles after 7 days at physiologic pH. From photochemical stability experiments irradiating at 415 nm, the dendritic derivatives containing triazole linkers were more susceptible to being degraded. All derivatives exhibited emission properties according to the length of each conjugate fragment. Fluorescence experiments evidenced the role of dendrons in preventing emission quenching by aggregation and exhibited differentiated emission behavior depending on the linker type (triazole or ester) between the chromophoric core and the polyester dendrons.

A Novel Study on the Self-Assembly Behavior of Poly(lactic-co-glycolic acid) Polymer Probed by Curcumin Fluorescence

Understanding the self-assembly behavior of block copolymers is of great importance due to their usefulness in a wide range of applications. In this work, the physical properties of poly(lactic-co-glycolic acid) (PLGA polymer) are studied for the first time in solution using the fluorescence technique and curcumin as a molecular probe. First, curcumin at a concentration of 2 μM was added to different concentrations of PLGA, and the fluorescence of curcumin was tracked. It was found that the critical micellar concentration (CMC) was equal to 0.31 g/L and the critical micellar temperature (CMT) was obtained to be 25 °C. Furthermore, an insight on the effect of NaCl salt on the CMC value of PLGA is assessed through curcumin probing. A decrease in the CMC has been observed with the increase in the concentration of NaCl, which could be due to the salting out effect. Moreover, in order to understand the aggregation behavior of PLGA in different solutions, CMC experiments were investigated using chloroform as a solvent. Results showed that the solvent does not affect the CMC value of the polymer; however, it only affects the shape of the obtained micelle forming a reversed micelle. Finally, fluorescence quenching of curcumin with hydrophobic cetyl-pyridinium bromide (CPB) and hydrophilic KI quenchers was established, where it was proved that curcumin is located near the hydrophobic pocket of the Stern layer of the PLGA micelle.

Optical spectroscopy study of the interaction between curcumin and acrylic polymers

This paper presents the results of a study conducted on the interaction between curcumin, a compound with several biomedical applications in traditional and modern medicine, and the acrylic polymers poly(methyl methacrylate), poly(ethyl methacrylate), and poly(n-butyl methacrylate), through photophysical experiments in curcumin/acrylic polymers casting films. Optical absorption intensity at ~340 nm increases relatively to its maximum at ~417 nm when the amount of curcumin in the polymeric film decreases, due to a significant change in the concentration of the isomers cis- or trans-form of curcumin, regardless of the acrylic polymer. Fluorescence (FL) spectra of the films depend on the curcumin concentration in the matrix with well-resolved line shape. They show two distinct bands, one at ~525 nm, for higher curcumin concentration (5.00 mmol.L^-1), related to the aggregated curcumin species, and another at ~465 nm, for lower concentration of curcumin (0.10 mmol.L^-1), related to the effects of the solvent on the conformational structure of the curcumin molecule and the presence of the trans-form of curcumin. The parameter K_agg, related to the contribution of the aggregated curcumin, shows the influence of the polymeric lateral chain length of the matrix in the de-aggregation of the curcumin. The Huang-Rhys factor indicates that curcumin aggregated species are conformationally more stable, and that the isolate species depends on the chemical environment and the matrix/curcumin interaction, decreasing its conformational degrees of freedom. Arrhenius plots, obtained via FL experiment in function of the sample temperature, show that, for higher curcumin concentration, the value for the relaxation energy process is not well defined, due the decrease in the interaction between the matrix and the curcumin molecules. With these results, it is possible to infer that the interaction matrix/curcumin must occur via lateral chemical alkyl groups.

Curcumin-Induced Membrane Property Changes in DMPC Multilamellar Vesicles and the Effects of Membrane-Destabilizing Molecules on Curcumin-Loaded Multilamellar Vesicles

Curcumin (CUR) is the major bioactive component of turmeric (Curcuma longa), commonly used as a spice and traditional medicine in India. CUR possesses a wide range of pharmacological benefits, including antioxidant, anticarcinogenic, antimutagenic, anti-inflammatory, anti-Alzheimer, and anti-Parkinson effects. The CUR-membrane interaction is believed to be the reason for such biological activity of CUR. Several research groups have modeled the interaction of CUR with artificial model lipid membranes using various techniques such as nuclear magnetic resonance (NMR), small-angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC). However, the mechanism of its action is still unclear. A fluorescent-probe-based technique could be advantageous to study the CUR-lipid membrane interaction due to its sensitivity toward the local environment and its multiparametric nature. In this work, we have used the intrinsic fluorescence properties of CUR to investigate CUR-induced physical property changes in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) multilamellar vesicles (MLVs) at various CUR concentrations. By rationalizing the results of steady-state fluorescence intensity, fluorescence anisotropy, temperature-dependent fluorescence intensity, temperature-dependent fluorescence anisotropy, and quenching experiments, we have proposed a model showing concentration-dependent effects of CUR on the DMPC bilayer membrane. We suggest that at low concentrations (≤1 mol %), CUR is homogeneously distributed in the DMPC bilayer membrane in both the solid gel (SG) and liquid crystalline (LC) phases. At high concentrations (>1 mol %), CUR molecules form segregated domains that fluidize both membrane phases. However, the CUR-induced fluidization is less pronounced in the LC phase as some CUR molecules from the domain partition into the bilayer core. Further, the effects of membrane-destabilizing molecules such as bile salts, capsaicin (CAP), and piperine (PIP) on CUR-loaded DMPC multilamellar vesicles were studied. Our work also shows that CUR has a stabilizing effect on the DMPC membrane at high concentrations.

Magnetoliposomes Incorporated in Peptide-Based Hydrogels: Towards Development of Magnetolipogels

A major problem with magnetogels is the encapsulation of hydrophobic drugs. Magnetoliposomes not only provide these domains but also improve drug stability and avert the aggregation of the magnetic nanoparticles. In this work, two magnetoliposome architectures, solid and aqueous, were combined with supramolecular peptide-based hydrogels, which are of biomedical interest owing to their biocompatibility, easy tunability, and wide array of applications. This proof-of-concept was carried out through combination of magnetoliposomes (loaded with the model drug curcumin and the lipid probe Nile Red) with the hydrogels prior to pH triggered gelation, and fluorescence spectroscopy was used to assess the dynamics of the encapsulated molecules. These systems allow for the encapsulation of a wider array of drugs. Further, the local environment of the encapsulated molecules after gelation is unaffected by the used magnetoliposome architecture. This system design is promising for future developments on drug delivery as it provides a means to independently modify the components and adapt and optimize the design according to the required conditions.

Effect of curcumin and cosolvents on the micellization of Pluronic F127 in aqueous solution

The drug solubilization capacity of poloxamers like Pluronic F127 (PF127, poloxamer 407) is dependent on the physical form of the polymer; i.e. the distribution between unimers, aggregates, and micelles. Further, the formation of micelles can alter the stability and pharmacological activity of a drug molecule. It is therefore important to understand how the micellization process is influenced by the addition of excipients and drug molecules. Curcumin is considered a photosensitizer in antimicrobial photodynamic therapy (aPDT). The aPDT effect is optimized at a poloxamer concentration just below the critical micellar concentration (CMC). We aimed to evaluate the effect of curcumin in the presence of 1% ethanol (EtOH) or dimethyl sulfoxide (DMSO) on PF127 micellization. These organic solvents are commonly used in topical preparations as a cosolvent or penetration enhancer (in the case of DMSO). The micellization process was investigated by UV-vis spectroscopy, dynamic light scattering (DLS), and differential scanning calorimetry (DSC). The micellization process of PF127 was slightly influenced by the addition of 1% EtOH or DMSO; however, the presence of 20 μM curcumin enhanced the effect. Micellization was favored in PBS compared to MilliQ water. Structures were formed between PF127 and curcumin at poloxamer concentrations ≥0.3 μM which facilitated solubilization of the photosensitizer. The optimal PF127 concentration required to solubilize 20 μM curcumin but avoid micellization was in the range 0.3 μM-0.04 mM in PBS in the presence of 1 % EtOH or DMSO. A careful consideration of the curcumin, cosolvents, and PF127 concentrations is required to enhance the curcumin solubility and prevent the PF127 micellization.

Formation, Physicochemical Stability, and Redispersibility of Curcumin-Loaded Rhamnolipid Nanoparticles Using the pH-Driven Method

The aim of the present work was to fabricate the curcumin-loaded rhamnolipid nanoparticles using the pH-driven method to enhance the physicochemical stability and redispersibility of curcumin. The mixture of curcumin and rhamnolipid could be spontaneously assembled into the curcumin-loaded rhamnolipid nanoparticles with a small size (107 nm) and negative charge (-45.5 mV). Curcumin molecules could bind to rhamnolipid molecules through hydrophobic effects and hydrogen bonds. The effect of different mass ratios of rhamnolipid and curcumin (1:2, 1:1, 2:1, 4:1, 6:1, and 8:1) on the functional property of the curcumin-loaded rhamnolipid nanoparticles was investigated. With the rise of rhamnolipid and curcumin mass ratio, the encapsulation efficiency of curcumin in the nanoparticles was increased from 44.59% to 81.12% and the loading capacity of curcumin was elevated from 10.14% to 31.67%. When the mass ratio of rhamnolipid and curcumin was 4:1, the curcumin-loaded rhamnolipid nanoparticles exhibited better physical stability, pH stability, and redispersibility. Moreover, the nanoparticles could effectively protect curcumin against the photodegradation and thermal degradation. Therefore, the rhamnolipid nanoparticles have the potential to be applied as a nanodelivery system for bioactive molecules in functional foods.

Introducing Tween-curcumin niosomes: preparation, characterization and microenvironment study

In this work, we report unusual niosomes (non-ionic surfactant based vesicles), prepared using non-ionic surfactant Tween 80 (T80) as well as Tween 20 (T20) and curcumin. Conventional niosomes consist of non-ionic surfactant and cholesterol. We found that, despite being a probiotic, curcumin plays a similar role to cholesterol in the formation and stabilization of niosomes. The prepared Tween-curcumin niosomes were characterised using Dynamic Light Scattering (DLS), zeta potential, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) techniques. The curcumin-induced micelle to vesicle transition in the Tween surfactants was investigated by DLS, zeta potential, fluorescence anisotropy, and fluorescence lifetime studies. At room temperature (298 K), the prepared niosomes were found to be stable; however, at a higher temperature (333 K), the niosomes degrade gradually and irreversibly to form micelles. The temperature-dependent vesicle to micelle degradation was monitored using fluorescence anisotropy, absorption, DLS and Differential Scanning Calorimetry (DSC) measurements. Further, the Tween-curcumin niosomes show a controlled release of curcumin, which could open up the possibility of multidrug therapy.

Interaction of carbon nanotubes with curcumin: Effect of temperature and pH on simultaneous static and dynamic fluorescence quenching of curcumin using carbon nanotubes

Curcumin (Cur) has medicinal properties, undergoes hydrolysis, and has low water solubility that limits its bioavailability and industrial usage. Different host molecules such as carbon nanotubes (CNT) can be useful in improving solubility and stabilizing Cur, therefore understanding the interaction of Cur with host molecules such as CNT is crucial. In this study, UV-visible light absorption and fluorescence spectroscopic techniques have been applied to reveal the interaction of Cur with CNT. Visible light absorption of Cur increases with CNT concentration, whereas fluorescence intensity of Cur is quenched in the presence of CNT. The obtained results confirm that fluorescence reduction is due to both static and dynamic quenching and is a result of the ground state and excited-state complex formation. The pH environment influences the quenching rate due to deprotonation of Cur at higher pH; excess OH- ion concentration in the solution further discourages electrostatic interaction between the deprotonated form of Cur with CNT. It is found that at lower temperatures (<35°C) dynamic quenching is much more dominant and at higher temperatures (45°C) static quenching is more dominant. The interaction is further supported using X-ray diffraction patterns and Fourier transform infrared spectra in the solid state, and suggests encapsulation of curcumin within the CNT. It is further evident that fluorescence quenching of Cur using CNT is further enhanced in the presence of several salts, as increase in ionic strength of the solution pushes the hydrophobic Cur molecule towards the CNT core by increasing the proximity between them.

A short review on chemical properties, stability and nano-technological advances for curcumin delivery

Introduction: Curcumin is a polyphenol found in turmeric that is derived from the rhizomes of Curcuma longa. Curcumin has received a worldwide attention due to being a major constituent of the traditional Chinese and Indian holistic systems, and due to its well-documented pharmacological effects against various diseases.Areas covered: In order to provide a better understanding of curcumin's biological activities, its chemical, structural, spectral and photophysical properties should be studied. Also, it is crucial to study the aqueous, spectral, photophysical, photochemical, and thermal stability. Such studies indicated that curcumin suffers from bioavailability problems such as low serum levels, limited tissue distribution, and excessive metabolism which all limit its therapeutic efficacy. This review summarizes different properties of curcumin, its stability, bioavailability problems, and recent nanotechnological approaches with special highlight on nanocapsules for curcumin delivery.Expert opinion: Poor bioavailability of curcumin could be overcome through recently emerging and promising nanotechnological approaches.

Ultra-High to Ultra-Low Drug-Loaded Micelles: Probing Host-Guest Interactions by Fluorescence Spectroscopy

Polymer micelles are an attractive means to solubilize water insoluble compounds such as drugs. Drug loading, formulations stability and control over drug release are crucial factors for drug-loaded polymer micelles. The interactions between the polymeric host and the guest molecules are considered critical to control these factors but typically barely understood. Here, we compare two isomeric polymer micelles, one of which enables ultra-high curcumin loading exceeding 50 wt.%, while the other allows a drug loading of only 25 wt.%. In the low capacity micelles, steady-state fluorescence revealed a very unusual feature of curcumin fluorescence, a high energy emission at 510 nm. Time-resolved fluorescence upconversion showed that the fluorescence life time of the corresponding species is too short in the high-capacity micelles, preventing an observable emission in steady-state. Therefore, contrary to common perception, stronger interactions between host and guest can be detrimental to the drug loading in polymer micelles.

Like Dissolves Like? A Comprehensive Evaluation of Partial Solubility Parameters to Predict Polymer-Drug Compatibility in Ultrahigh Drug-Loaded Polymer Micelles

Despite decades of research, our understanding of the molecular interactions between drugs and polymers in drug-loaded polymer micelles does not extend much beyond concepts such as "like-dissolves-like" or hydrophilic/hydrophobic. However, polymer-drug compatibility strongly affects formulation properties and therefore the translation of a formulation into the clinics. Specific interactions such as hydrogen-bonding, π-π stacking, or coordination interactions can be utilized to increase drug loading. This is commonly based on trial and error and eventually leads to an optimized drug carrier. Unfortunately, due to the unique characteristics of each drug, the deduction of advanced general concepts remains challenging. Furthermore, the introduction of complex moieties or specifically modified polymers hampers systematic investigations regarding polymer-drug compatibility as well as clinical translation. In this study, we reduced the complexity to isolate the crucial factors determining drug loading. Therefore, the compatibility of 18 different amphiphilic polymers for five different hydrophobic drugs was determined empirically. Subsequently, the obtained specificities were compared to theoretical compatibilities derived from either the Flory-Huggins interaction parameters or the Hansen solubility parameters. In general, the Flory-Huggins interaction parameters were less suited to correctly estimate the experimental drug solubilization compared to the Hansen solubility parameters. The latter were able to correctly predict some trend regarding good and poor solubilizers, yet the overall predictive strength of Hansen solubility parameters is clearly unsatisfactory.

Novel Dual Mitochondrial and CD44 Receptor Targeting Nanoparticles for Redox Stimuli-Triggered Release

In this work, novel mitochondrial and CD44 receptor dual-targeting redox-sensitive multifunctional nanoparticles (micelles) based on oligomeric hyaluronic acid (oHA) were proposed. The amphiphilic nanocarrier was prepared by (5-carboxypentyl)triphenylphosphonium bromide (TPP), oligomeric hyaluronic acid (oHA), disulfide bond, and curcumin (Cur), named as TPP-oHA-S-S-Cur. The TPP targeted the mitochondria, the antitumor drug Cur served as a hydrophobic core, the CD44 receptor targeting oHA worked as a hydrophilic shell, and the disulfide bond acted as a connecting arm. The chemical structure of TPP-oHA-S-S-Cur was characterized by ¹HNMR technology. Cur was loaded into the TPP-oHA-S-S-Cur micelles by self-assembly. Some properties, including the preparation of micelles, morphology, redox sensitivity, and mitochondrial targeting, were studied. The results showed that TPP-oHA-S-S-Cur micelles had a mean diameter of 122.4 ± 23.4 nm, zeta potential - 26.55 ± 4.99 mV. In vitro release study and cellular uptake test showed that TPP-oHA-S-S-Cur micelles had redox sensibility, dual targeting to mitochondrial and CD44 receptor. This work provided a promising smart multifunctional nanocarrier platform to enhance the solubility, decrease the side effects, and improve the therapeutic efficacy of anticancer drugs.

Photophysical studies on curcumin-sophorolipid nanostructures: applications in quorum quenching and imaging

Sophorolipid biosurfactants are biodegradable, less toxic and FDA approved. The purified acidic form of sophorolipid is stimuli-responsive with self-assembling properties and used for solubilizing hydrophobic drugs. This study encapsulated curcumin (CU) with acidic sophorolipid (ASL) micelles and analysed using photophysical studies like UV-visible spectroscopy, photoluminescence (PL) spectroscopy and time-correlated single photon counting (TCSPC). TEM images have revealed ellipsoid micelles of approximately 100 nm size and were confirmed by dynamic light scattering. The bacterial fluorescence uptake studies showed the uptake of formed CUASL nanostructures into both Gram-positive and Gram-negative bacteria. They also showed quorum quenching activity against Pseudomonas aeruginosa. The results have demonstrated this system has potential theranostic applications.