Nanoimmunotherapy: application of nanotechnology for sustained and targeted delivery of antigens to dendritic cells

Nanotechnology in cervical cancer immunotherapy: Therapeutic vaccines and adoptive cell therapy

Immunotherapy is an emerging method for the treatment of cervical cancer and is more effective than surgery and radiotherapy, especially for recurrent cervical cancer. However, immunotherapy is limited by adverse effects in clinical practice. In recent years, nanotechnology has been widely used for tumor diagnosis, drug delivery, and targeted therapy. In the setting of cervical cancer, nanotechnology can be used to actively or passively target immunotherapeutic agents to tumor sites, thereby enhancing local drug delivery, reducing drug adverse effects, achieving immunomodulation, improving the tumor immune microenvironment, and optimizing treatment efficacy. In this review, we highlight the current status of therapeutic vaccines and adoptive cell therapy in cervical cancer immunotherapy, as well as the application of lipid carriers, polymeric nanoparticles, inorganic nanoparticles, and exosomes in this context.

Polymeric hydrogel as a vitreous substitute: current research, challenges, and future directions

Vitreoretinal surgery is an essential approach to treat proliferative diabetic vitreopathy, retinal detachment, retinal tear, ocular trauma, and macular holes. The removal of the natural vitreous and the replacement with substitutes are critical steps for retina reattachment. Vitreous substitutes including silicone oil (SiO), air, sulfur hexafluoride (SF₆), and perfluoropropane (C₃F₈), have been widely applied in clinical practice. However, these substitutes are reported to cause complications such as emulsification, high intraocular pressure, and lens opacification. Polymeric hydrogels are a kind of material with favorable physical, mechanical properties, and adaptable biocompatibility, thus being highly expected to be ideal vitreous substitutes. Despite years of research, very few polymeric hydrogels can be applied practically in the vitreous cavity. In this review, we focus on the development of polymeric natural-based hydrogels and synthetic hydrogels. Particularly, we pay attention to recent advances in the novel stimuli-response and self-assembly supramolecular hydrogels. Characterized by easy injectability and long residence time, this kind of hydrogel becomes the potentially promising candidates for ideal vitreous substitutes. Finally, we evaluate the current challenges and provide the future directions of vitreous substitutes.

Foldable capsular vitreous body implantation for treatment of traumatic retinal detachment: two case reports

Retinal detachment caused by severe ocular trauma is a type of refractory vitreoretinal disease. Current treatment methods include vitrectomy combined with silicone oil tamponade. However, long-term use of silicone oil tamponade has various complications, including a risk of silicone oil dependence that eventually leads to eyeball atrophy and enucleation. Foldable capsular vitreous bodies (FCVBs) offer a good solution for these problems. However, FCVBs have not been used in large-scale clinical applications and few cases have been reported in the published literature. The main use of FCVBs, based on current evidence, is in the treatment of the relatively few (but important) patients whose eyes have no visual potential; the aim of treatment in these patients is globe preservation, rather than restoration of vision. Here, we describe two patients who underwent FCVB implantation. The findings in these patients indicated that FCVBs can effectively support the vitreous cavity and detached retina. FCVB implantation may thus offer a safe and effective method for treatment of severe retinal detachment, avoiding the inconvenience caused by silicone oil dependence and enucleation. To confirm its long-term usefulness in clinical applications, many additional case reports are needed.

Macro- and Microscale Properties of the Vitreous Humor to Inform Substitute Design and Intravitreal Biotransport

Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested in vitro, has been hypothesized to be different in vivo. Future studies should focus on testing the mechanical properties of the vitreous in situ or in vivo. In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport.

Study on the effectiveness and safety of Foldable Capsular Vitreous Body implantation

Background

Foldable capsular vitreous body (FCVB) was designed to treat severe retinal detachment. The aim of this study was to evaluate the efficacy and safety of the implantation of foldable capsular vitreous body in 1-year follow-up.

Methods

A retrospective analysis was conducted for 20 patients with severe ocular trauma or silicone oil (SO) dependent eyes underwent vitrectomy and FCVB implantation in a 1-year follow-up. All treated eyes were peformed clinical examinations involved the visual acuity (VA) examination, Goldmann applanation tonometer, noncontact specular microscopy, fundus photography, B-Scan examination and optical coherence tomography (OCT). The groups were compared with t-test and the McNemar - Bowker test.

Results

In 1-year follow-up, 20 eyes were evaluated in the study. FCVB well supported the vitreous retina in all treated eyes, and 6 treated eyes achieved retinal reattachment 12 months after FCVB implantation. There were no significant differences in VA before and after FCVB implantation (P = 1.000). In addition, the postoperative IOP markedly elevated from the preoperative IOP of 12.90 ± 7.06 mmHg to 15.15 ± 3.36 mmHg (P = 0.000017). The intraocular pressure (IOP) of 10 eyes maintained at a normal level after surgeries. The other 10 eyes showed slightly lower IOP within the acceptable level. Though two patients developed keratopathy and ocular inflammation respectively, other treated eyes were symmetric with fellow eyes showing satisfactory appearance. Moreover, there was no SO emulsification or leakage happened in the observation.

Conclusions

FCVB implantation was an effective and safe treatment in the eyes with severe retinal detachment.

Mannose functionalized plain and endosomolytic nanocomposite(s)-based approach for the induction of effective antitumor immune response in C57BL/6 mice melanoma model

The goal of present study to assess the antigen specific immunopotentiation effect of mannose functionalized endosomolytic and conventional nanocomposite(s) based combination approach using C57BL/6 mice melanoma model. Endosomolytic and conventional nanocomposite(s) were prepared by double emulsification method. The optimized formulation was extensively characterized for average particle size, zeta potential and PDI of nanocomposite(s) which were measured in range of ≈200 nm, 0.111 ± 0.024, -23.4 ± 2.0 mV, respectively. pH-dependent morphological changes in the surface of MRPRPNs and PRPNs were analyzed by using surface electron microscopy at different time intervals. The cellular uptake assessment of developed formulations were followed by using RAW 264.7 macrophage cell lines. Results revealed that after immunizing B16F10 melanoma cells implanted C57BL/6 mice with combination [endosomolytic and conventional nanocomposite(s)] of nanocomposite(s), a significant increase in the interleukins level i.e. IL-2, IFN-ϒ, IL-12 and IL-6 and OVA Ag(s) specific antibody responses were recorded. Consequently, a strong immunological response was elicited with specific polarization contributing to humoral and activation of CD8⁺ to cellular responses. Finding of histological examination also support the potential of therapeutic outcome. The present approach based on mannose surface functionalization for targeting to antigen presenting cells and pH-dependent prompt endosomal release and escape can be a promising system for efficient cancer immunotherapy.

Immunochemotherapy mediated by thermosponge nanoparticles for synergistic anti-tumor effects

The efficacy of immunotherapy was demonstrated to be compromised by reduced immunogenicity of tumor cells and enhanced suppressive properties of the tumor microenvironment in cancer treatment. There is growing evidence that low-dose chemotherapy can modulate the immune system to improve the anti-tumor effects of immunotherapy through multiple mechanisms, including the enhancement of tumor immunogenicity and reversal of the immunosuppressive tumor microenvironment. Here, we fabricated thermosponge nanoparticles (TSNs) for the co-delivery of chemotherapeutic drug paclitaxel (PTX) and immunostimulant interleukin-2 (IL-2) to explore the synergistic anti-tumor effects of chemotherapy and immunotherapy. The distinct temperature-responsive swelling/deswelling character facilitated the effective post-entrapment of cytokine IL-2 in nanoparticles by a facile non-solvent mild incubation method with unaffected bioactivity and favorable pharmacokinetics. PTX and IL-2 co-loaded TSNs exhibited significant inhibition on tumor growth and metastasis, and prolonged overall survival for tumor-bearing mice compared with the corresponding monotherapies. The synergistic effect was evidenced from the remodeled tumor microenvironment in which low-dose chemotherapeutics disrupted the immunosuppressive tumor microenvironment and enhanced tumor immunogenicity, and immunostimulant cytokine promoted the anti-tumor immune response of immune effector cells. The immunochemotherapy mediated by this thermosponge nanoplatform may provide a promising treatment strategy against cancer.

Comparative assessment of lipid based nano-carrier systems for dendritic cell based targeting of tumor re-initiating cells in gynecological cancers

We aimed to identify an optimum nano-carrier system to deliver tumor antigen to dendritic cells (DCs) for efficient targeting of tumor reinitiating cells (TRICs) in gynecological malignancies. Different lipid based nano-carrier systems i.e. liposomes, ethosomes and solid lipid nanoparticles (SLNPs) were examined for their ability to activate DCs in allogeneic settings. Out of these three, the most optimized formulation was subjected for cationic and mannosylated surface modification and pulsed with DCs for specific targeting of tumor cells. In both allogeneic and autologous trials, SLNPs showed a strong ability to activate DCs and orchestrate specific immune responses for targeting TRICs in gynecological malignancies. Our findings suggest that the mannosylated form of SLNPs is a suitable molecular vector for DC based therapeutics. DCs pulsed with mannosylated SLNPs may be utilized as adjuvant therapy for specific removal of TRICs to benefit patients from tumor recurrence.

Combinations in multimodality treatments and clinical outcomes during cancer

Combination approach could be easily considered as the future of therapeutics in all pathological states including cancer. Scientists are trying different combinations in order to determine synergism among different therapeutics which ultimately helps in the improved and more efficient management of the affected patients. Combination of multi-chemotherapeutic agents, or multi-drug therapy, may be the most commonly used strategy for cancer treatment. Monotherapy causes drug resistance and loses its response in patients after several cycles of treatment. While combining different anticancer drugs together for cancer treatment, as in the case of the cocktail therapy for HIV, not only overcomes the drug resistance but also leads to a synergistic effect, therefore showing prolonged survival for patients. The present review article is focused on different combinations in use for better efficiency of therapeutics against cancer. We searched the electronic database PubMed for pre-clinical as well as clinical controlled trials reporting diagnostic as well as therapeutic advances of various combinations in cancer. It was observed clearly that combination approach is better in various aspects including increase in efficacy, specificity and decline in the unwanted side effects.

Nanoengineered strategies to optimize dendritic cells for gastrointestinal tumor immunotherapy: from biology to translational medicine

Nanomedicine may play an important role in improving the clinical efficacy of dendritic cell-based immunotherapy against GI tract malignancies. Dendritic cell-based vaccines have proven their effectiveness against different established GI tract tumors, yet their success is mainly hindered by the strong tumor-induced suppressive microenvironment. The sustained and targeted release of tumor antigens to dendritic cells using different nanoengineered approaches would be an efficient strategy to overcome established immune tolerance. Encapsulation would result in low diffusivity, restricted movement, effective crosspresentation and enhanced T-cell responses. These nanotherapy-based approaches will certainly help with the designing of clinically translatable dendritic cell-based therapeutic vaccines and facilitate the selective removal of residual disease in gastrointestinal cancer patients following standard treatments.

Comparison of inhibitory effects of 17-AAG nanoparticles and free 17-AAG on HSP90 gene expression in breast cancer

BACKGROUND

HSP90 may be overexpressed in cancer cells which are greatly dependent on Hsp90 function. Geldanamycin derivative 17 allylamino-17-demethoxygeldanamycin (17-AAG) inhibits the function and expression of HSP90. 17-AAG has poor water-solubility which is a potential problem for clinical practice. In this study for improving the stability and solubility of molecules in drug delivery systems we used a β-cyclodextrin- 17AAG complex.

MATERIALS AND METHODS

To assess cytotoxic effects of β-cyclodextrin-17AAG complexes and free 17AAG, colorimetric cell viability (MTT) assays were performed. Cells were treated with equal concentrations of β-cyclodextrin- 17AAG complex and free 17AAG and Hsp90 gene expression levels in the two groups was compared by real-time PCR.

RESULTS

MTT assay confirmed that β-cyclodextrin- 17AAG complex enhanced 17AAG cytotoxicity and drug delivery in T47D breast cancer cells. The level of Hsp90 gene expression in cells treated with β-cyclodextrin- 17AAG complex was lower than that of cells treated with free 17AAG (P=0.001).

CONCLUSIONS

The results demonstrated that β-cyclodextrin- 17AAG complexes are more effective than free 17AAG in down-regulating HSP90 expression due to enhanced β-cyclodextrin-17AAG uptake by cells. Therefore, β-cyclodextrin could be superior carrier for this kind of hydrophobic agent.

Recent advances in targeted nanoparticles drug delivery to melanoma

Melanoma is one of the most aggressive skin cancers, notorious for its high multidrug resistance and low survival rate. Conventional therapies (e.g., dacarbazine, interferon-alpha-2b and interleukin-2) are limited by low response rate and demonstrate no overall survival benefit. Novel targeted therapies (e.g., vemurafenib, dabrafenib and trametinib) have higher initial response rate and clear impact on the overall survival, but relapse usually occurs within 6 to 9 months. Although immunotherapy (e.g., ipilimumab, pembrolizumab and nivolumab) can achieve long-term and durable response, rate of adverse events is extremely high. With the development of nanotechnology, the applications of nanocarriers are widely expected to change the landscape of melanoma therapy for foreseeable future. In this review, we will relate recent advances in the application of multifunctional nanocarriers for targeted drug delivery to melanoma, in melanoma nanotheranostics and combination therapy, and nanopharmaceutical associated melanoma clinical trials, followed by challenges and perspectives. From the clinical editor: The team of authors describes the current treatment regimes of malignant melanoma emphasizing the importance of achieving a better efficacy and the need to develop a better understanding of melanoma tumorigenesis.

Graphene: Synthesis, bio-applications, and properties

The properties of graphene, carbon sheets that are only one atom wide, have led researchers and companies to consider its synthesis, properties, and the applications in numerous fields. High-quality graphene is physically powerful, light, nearly transparent, and an exceptional conductor of heat and electricity. Its interactions with other materials and with light and its naturally two-dimensional nature produce unique properties, such as the bipolar transistor effect, ballistic transport of charges, and large quantum oscillations. The following review introduces the many potential applications of graphene.

Silver nanoparticles: Synthesis methods, bio-applications and properties

Silver nanoparticles size makes wide range of new applications in various fields of industry. Synthesis of noble metal nanoparticles for applications such as catalysis, electronics, optics, environmental and biotechnology is an area of constant interest. Two main methods for Silver nanoparticles are the physical and chemical methods. The problem with these methods is absorption of toxic substances onto them. Green synthesis approaches overcome this limitation. Silver nanoparticles size makes wide range of new applications in various fields of industry. This article summarizes exclusively scalable techniques and focuses on strengths, respectively, limitations with respect to the biomedical applicability and regulatory requirements concerning silver nanoparticles.

Preliminary study on retinal vascular and oxygen-related changes after long-term silicone oil and foldable capsular vitreous body tamponade

Silicone oil has been the only long-term vitreous substitute used in the treatment of retinal detachment since 1962 by Cibis. Nevertheless, its effects on retinal vascular morphology and oxygen supply to the retina are ambiguous in current research. We previously invented a foldable capsular vitreous body (FCVB) to use as a new vitreous substitute in the treatment of severe retinal detachment, but its effects on the retinal vessel were unknown. Therefore, in this study, a standard three-port pars plana vitrectomy (PPV) was performed on the right eye of each rabbit and then silicone oil and FCVB were injected into the vitreous cavity as vitreous substitutes. After 180 days of retention, the retinal vascular morphology did not display any distinct abnormalities, and hypoxia-induced factor-1alpha (HIF-1α) and vascular endothelial growth factor (VEGF) did not vary markedly during the observation period in silicone oil tamponade- and FCVB-implanted eyes. This study may suggest that silicone oil and FCVB tamponade in rabbit eyes did not cause retinal vascular pathologic changes or retinal hypoxia for 180 days.

A study of the dexamethasone sodium phosphate release properties from a periocular capsular drug delivery system

The aim of this study was to investigate whether a periocular capsular drug delivery system (DDS) can release dexamethasone sodium phosphate (DEXP) in vitro and in vivo to the posterior segment of rabbit's eye. In vitro, the periocular capsular DDS containing 2 mg/ml or 5 mg/ml DEXP was immersed in modified Franz diffusion cell. Four-hundred microliters of liquid was aspirated at 0.5, 1, 2, 4, 8, 24 and 48 h for determination. In vivo, the DEXP-filled periocular capsular DDS was implanted into the sub-Tenon's sac of the New Zealand rabbit. DEXP concentration at the serum aqueous humor, cornea, iris, lens, ciliary body, vitreous, retina, choroids and sclera was quantified at 1, 3, 7, 14, 28 and 56 d after implantation. The DEXP concentration was determined by ultra-performance liquid chromatography-tandem mass spectrometry. In vitro, the periocular capsular DDS released the DEXP in time-dependent manner from 1/2 to 48 h. In vivo, the concentrations of the DEXP at the retina, choroids, ciliary body and iris were 123.11 (91.23, 732.61) ng/g, 362.46 ± 330.46 ng/g, 71.64 (71.35, 180.21) ng/g and 192.50 ± 42.66 ng/g, respectively, at 56 d after implantation. Minimal DEXP was found in the aqueous, serum and vitreous. Our results demonstrated that DEXP could be sustained released from the periocular capsular DDS, which indicated that the periocular capsular DDS might be a potential candidate of transscleral drug delivery for the management of posterior segment diseases.

Physicochemical characteristics of Fe3O4 magnetic nanocomposites based on Poly(N-isopropylacrylamide) for anti-cancer drug delivery

BACKGROUND

Hydrogels are a class of polymers that can absorb water or biological fluids and swell to several times their dry volume, dependent on changes in the external environment. In recent years, hydrogels and hydrogel nanocomposites have found a variety of biomedical applications, including drug delivery and cancer treatment. The incorporation of nanoparticulates into a hydrogel matrix can result in unique material characteristics such as enhanced mechanical properties, swelling response, and capability of remote controlled actuation.

MATERIALS AND METHODS

In this work, synthesis of hydrogel nanocomposites containing magnetic nanoparticles are studied. At first, magnetic nanoparticles (Fe3O4) with an average size 10 nm were prepared. At second approach, thermo and pH-sensitive poly (N-isopropylacrylamide -co-methacrylic acid-co-vinyl pyrrolidone) (NIPAAm-MAA- VP) were prepared. Swelling behavior of co-polymer was studied in buffer solutions with different pH values (pH=5.8, pH=7.4) at 37 °C. Magnetic iron oxide nanoparticles (Fe3O4) and doxorubicin were incorporated into copolymer and drug loading was studied. The release of drug, carried out at different pH and temperatures. Finally, chemical composition, magnetic properties and morphology of doxorubicin-loaded magnetic hydrogel nanocomposites were analyzed by FT- IR, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM).

RESULTS

The results indicated that drug loading efficiency was increased by increasing the drug ratio to polymer. Doxorubicin was released more at 40 °C and in acidic pH compared to that 37 °C and basic pH.

CONCLUSIONS

This study suggested that the poly (NIPAAm-MAA-VP) magnetic hydrogel nanocomposite could be an effective carrier for targeting drug delivery systems of anti-cancer drugs due to its temperature sensitive properties.

Effects of Caryota mitis profilin-loaded PLGA nanoparticles in a murine model of allergic asthma

Background

Pollen allergy is the most common allergic disease. However, tropical pollens, such as those of Palmae, have seldom been investigated compared with the specific immunotherapy studies done on hyperallergenic birch, olive, and ragweed pollens. Although poly(lactic-co-glycolic acid) (PLGA) has been extensively applied as a biodegradable polymer in medical devices, it has rarely been utilized as a vaccine adjuvant to prevent and treat allergic disease. In this study, we investigated the immunotherapeutic effects of recombinant Caryota mitis profilin (rCmP)-loaded PLGA nanoparticles and the underlying mechanisms involved.

Methods

A mouse model of allergenic asthma was established for specific immunotherapy using rCmP-loaded PLGA nanoparticles as the adjuvant. The model was evaluated by determining airway hyperresponsiveness and levels of serum-specific antibodies (IgE, IgG, and IgG2a) and cytokines, and observing histologic sections of lung tissue.

Results

The rCmP-loaded PLGA nanoparticles effectively inhibited generation of specific IgE and secretion of the Th2 cytokine interleukin-4, facilitated generation of specific IgG2a and secretion of the Th1 cytokine interferon-gamma, converted the Th2 response to Th1, and evidently alleviated allergic symptoms.

Conclusion

PLGA functions more appropriately as a specific immunotherapy adjuvant for allergen vaccines than does conventional Al(OH)₃ due to its superior efficacy, longer potency, and markedly fewer side effects. The rCmP-loaded PLGA nanoparticles developed herein offer a promising avenue for specific immunotherapy in allergic asthma.

A novel vitreous substitute of using a foldable capsular vitreous body injected with polyvinylalcohol hydrogel

Hydrogels may be the ideal vitreous substitutes due to their wonderful physical features and biocompatibility. However, their drawbacks, short residence time, and biodegradation in vivo, have led to the fact that none of them have been approved for clinical use. In this study, we developed a novel approach of using a foldable capsular vitreous body (FCVB) injected with polyvinylalcohol (PVA) hydrogel as a vitreous substitute for long-term tamponade. The 3% PVA hydrogel that was cross-linked by gamma irradiation showed good rheological and physical properties and had no toxicity in vitro. After 180 days retention, the 3% PVA hydrogel inside FCVB remained transparent and showed good viscoelasticity without biodegradation and showed good biocompatibility and retina support. This new approach may develop into a valuable tool to improve the stability performance of PVA hydrogel as a vitreous substitute and to extend the application function of FCVB for long-term implantation in vitreous cavity.

Combinational delivery of lipid-enveloped polymeric nanoparticles carrying different peptides for anti-tumor immunotherapy

AIM

The authors aimed to investigate whether nanotechnology-based delivery of antigenic peptides is feasible for efficiently inducing anti-tumor cytotoxic T lymphocyte responses through vaccination.

MATERIALS & METHODS

Three different murine melanoma antigens were entrapped in lipid-coated poly(D,L-lactide-co-glycolide) nanoparticles (NPs) by the double emulsion method.

RESULTS

The loading efficiency of hydrophilic peptides was greatly improved when lipids were introduced to formulate lipid-coated NPs. The lipid-coated NPs carrying a single peptide and/or combinations of multiple lipid-coated NPs carrying antigenic peptides were characterized in vitro and in vivo in a C57/BL6 (B6) mouse model. Both the single melanoma antigen peptide-loaded NPs and combinational delivery of lipid-coated NPs carrying different peptides could induce antigen-specific T-cell responses. However, single peptide-loaded NPs failed to significantly delay the growth of subcutaneously inoculated B16 melanoma cells in a prophylactic setting. By contrast, the combinational delivery of lipid-coated NPs carrying different peptides significantly suppressed growth of inoculated B16 melanoma cells.

Assessment of tumor antigen-loaded solid lipid nanoparticles as an efficient delivery system for dendritic cell engineering

Aim: The work attempts to overcome tumor-associated immune tolerance using a surface-modified solid lipid nanoparticle (SLNP) delivery system for dendritic cell (DC) immunotherapy. Materials & methods: Different formulations of SLNPs (SLNPs-alone, cationic SLNPs and mannosylated SLNPs) were prepared using tumor cell lysates. Prepared nanoparticles were characterized and their ability to activate DCs to induce a tumor cell-specific response was assessed. Results: SLNPs induced a strong phagocytic signal to DCs without any significant toxicity. Comparatively, mannosylated SLNPs evoked an optimum and effective cell-mediated immune response with no significant toxicity. Conclusion: Surface-modified SLNPs may play a pivotal role in designing a clinically translatable DC-based immunotherapy for gastrointestinal malignancies. This novel approach may also facilitate the treatment of residual disease, following standard therapy.

Original submitted 9 February 2012; Revised submitted 19 August 2012; Published online 14 January 2013

Avidin functionalized maghemite nanoparticles and their application for recombinant human biotinyl-SERCA purification

We report on the surface characterization, functionalization, and application of stable water suspensions of novel surface active maghemite nanoparticles (SAMNs), characterized by a diameter of 11 ± 2 nm and possessing peculiar colloidal properties and surface interactions. These features permitted the acquisition of titration curves and aqueous UV-vis spectra and suggested a role played by surface under-coordinated iron atoms. This new class of nanoparticles was obtained through an easy, inexpensive, one-step, green procedure and functionalized with ligands of high biotechnological interest, such as biotin and avidin, by simple incubation in aqueous solution. Bound avidin was determined by measuring the disappearance of free avidin absorbance at 280 nm, as a function of increasing nanoparticle concentration, showing the presence of 10 ± 3 avidin molecules per nanoparticle. The biological activity of the SAMN@avidin complex was evaluated and the number of available biotin binding sites was determined, using biotinyl-fluorescein as a probe, showing that each bound avidin molecule is able to bind 2.8 ± 0.8 biotin molecules, confirming the maintenance of biological activity and excellent binding capacity of the SAMN@avidin complex. Furthermore a Langmuir isotherm model was used to describe the biomolecule specific monolayer adsorption onto the particle surface, and in the case of avidin, the maximum adsorption capacity was 100 ± 27 μg avidin/mg SAMN, whereas the binding constant is 45.18 μL μg(-1). The SAMN@avidin complex was characterized by UV-vis spectroscopy, quartz crystal microbalance, FTIR spectroscopy, and transmission electron microscopy. Finally, SAMN@avidin was applied for the large scale purification of recombinant biotinylated human sarco/endoplasmic reticulum Ca(2+)-ATPase (hSERCA-2a), expressed by Saccharomyces cerevisiae. The protein was magnetically purified, and about 500 μg of a 70% pure hSERCA-2a were recovered from 4 L of yeast culture, with a purification yield of 64%.

In Vivo Toxicity of Intravenously Administered Silica and Silicon Nanoparticles

Both silicon and silica nanoparticles (SiNPs and SiO₂NPs, respectively) are currently considered to be promising carriers for targeted drug delivery. However, the available data on their in vivo toxicity are limited. The present study was aimed at investigation of SiNP and SiO₂NP (mean diameter 10 and 13 nm, respectively) toxicity using both morphological and functional criteria. Hematological and biochemical parameters were assessed in Sprague-Dawley rats 5, 21 and 60 days after administration of NPs. Inner ear function was determined using otoacoustic emission testing at 21 and 60 days after infusion of NPs. Furthermore, the histological structure of liver, spleen and kidney samples was analyzed. Intravenous infusion of SiNPs or SiO₂NPs (7 mg/kg) was not associated with significant changes in hemodynamic parameters. Hearing function remained unchanged over the entire observation period. Both inter- and intragroup changes in blood counts and biochemical markers were non-significant. Histological findings included the appearance of foreign body-type granulomas in the liver and spleen as well as microgranulation in the liver after administration of NPs. The number of granulomas was significantly lower after administration of SiNPs compared with SiO₂NPs. In conclusion, both tested types of NPs are relatively biocompatible nanomaterials, at least when considering acute toxicity.

Drug delivery via lipoprotein-based carriers: answering the challenges in systemic therapeutics

Plasma lipoproteins are transporters of lipids and other hydrophobic molecules in the mammalian circulation. Lipoproteins also have a strong potential to serve as drug-delivery vehicles due to their small size, long residence time in the circulation and high-drug payload. Consequently, lipoproteins and synthetic/reconstituted lipoprotein preparations have been evaluated with increasing interest towards clinical applications, particularly for cancer diagnostics/imaging and chemotherapy. In this review, past and current studies on lipoproteins and similar alternative drug carriers are discussed regarding their suitability as agents to deliver drugs, primarily to cancer cells and tumors. A lipoprotein-based delivery strategy may also provide a novel platform for improving the therapeutic efficacy of drugs that have previously been judged unsuitable or had only limited application due to poor solubility. An additional, and perhaps the most important aspect of the drug-delivery process via lipoprotein-type carriers, is the receptor-mediated uptake of the payload from the lipoprotein complex. Monitoring the expression of specific receptors prior to treatment could, thus, give rise to efficient selection of optimally responsive patients, resulting in a successful personalized therapy regimen.

Magnetic nanoparticles: preparation, physical properties, and applications in biomedicine

Finally, we have addressed some relevant findings on the importance of having well-defined synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the preparation of monodisperse samples of relatively large quantities not only with similar physical features, but also with similar crystallochemical characteristics. Then, different methodologies for the functionalization of the prepared MNPs together with the characterization techniques are explained. Theorical views on the magnetism of nanoparticles are considered.