N -Vinyl imidazole was grafted onto sodium alginate (P N VI- g -NaAlg) through a free radical polymerization technique in aqueous solution using potassium persulfate (K ₂ S ₂ O ₈ , KPS) initiator material.

4D printing of smart materials for regenerative medicine applications.

Chlorophyll (Chl) is a promising natural photosensitizer (PS) in photodynamic treatment (PDT). Mesoporous silica nanoparticles (MSNs) were chosen to increase the effectiveness of PDT. This study aimed to evaluate the synergistic efficacy of chlorophyll-loaded mesoporous silica nanoparticles (Chl-MSNs) with photodynamic therapy (PDT) and to investigate their potential toxicity in HepG2, MDA-MB-231, and HSF cell lines. Chl-MSNs were prepared via the physical adsorption method. TEM, DLS, and zeta potential examined morphology, size, and surface characteristics. MSNs and Chl-MSNs were characterized using the same techniques. HPLC was used to assess the encapsulation efficiency. At pH 7.4, an in vitro release experiment of Chl-MSNs was performed. Chl, MSNs, and Chl-MSNs were applied to the three cell lines at different concentrations and subjected to red (650 nm) and blue (450–500 nm) lasers. MSNs and Chl-MSNs’ sizes were 90.338 ± 38.49 nm and 123.84 ± 15.67 nm, respectively, as obtained by TEM; the hydrodynamic diameter for MSNs (93.69 ± 20.53 nm) and Chl-MSNs (212.95 ± 19.76 nm); and their zeta potential values are − 16.7 ± 2.19 mV and − 18.84 ± 1.40 mV. The encapsulation efficiency of Chl-MSNs was 70%. Chl-MSNs displayed no toxicity in dark conditions but showed excellent photostability under blue and red light exposure. Furthermore, using Chl over Chl-MSNs has a higher PDT efficiency than the tested cell lines. Chl-MSNs have the potential to be an effective delivery system. PDT proved to be an essential technique for cancer treatment. Blue laser is recommended over red laser with Chl and MSNs for destroying cancer cells. Graphical Abstract

Encapsulation, specifically microencapsulation is an old technology with increasing applications in pharmaceutical, agrochemical, environmental, food, and cosmetic spaces. In the past two decades, the advancements in the field of nanotechnology opened the door for applying the encapsulation technology at the nanoscale level. Nanoencapsulation is highly utilized in designing effective drug delivery systems (DDSs) due to the fact that delivery of the encapsulated therapeutic/diagnostic agents to various sites in the human body depends on the size of the nanoparticles. Compared to microencapsulation, nanoencapsulation has superior performance which can improve bioavailability, increase drug solubility, delay or control drug release and enhance active/passive targeting of bioactive agents to the sites of action. Encapsulation, either micro- or nanoencapsulation is employed for the conventional pharmaceuticals, biopharmaceuticals, biologics, or bioactive drugs from natural sources as well as for diagnostics such as biomarkers. The outcome of any encapsulation process depends on the technique employed and the encapsulating material. This chapter discusses in details (1) various physical, mechanical, thermal, chemical, and physicochemical encapsulation techniques, (2) types and classifications of natural polymers (polysaccharides, proteins, and lipids) as safer, biocompatible and biodegradable encapsulating materials, and (3) the recent advances in using lipids for therapeutic and diagnostic applications. Polysaccharides and proteins are covered in the second part of this chapter.