. 2023 Jun 23;24(7):2957–2981. doi: 10.1021/acs.biomac.3c00098

Table 4. SF Modified by a Variety of Monomers, Including MA, IEM, GMA, and CA and Their Applications.

grafted monomer	degumming approach	polymer named	cells	applications	significant observations	ref
grafted monomer	extraction	polymer named	cells	applications	significant observations	ref
MA	0.02 M Na₂CO₃, 30 min	SFMA	3T3 murine fibroblasts	bone tissue engineering	high cell viability (over 95% in 1st and 4th day)	(26)
	9.3 M LiBr				improved mechanical properties (70 kPa for 5.2% SFMA)
					supporting cell growth
					tuning the cell behavior with changing hydrogel stiffness and hydrophilicity
MA	0.02 M Na₂CO₃, 60 °C, 30 min	SFMA	B16F10 melanoma cells	antitumor effects	effective photodynamic	(93)
	9.3 M LiBr, 60 °C, 30 min		RAW264.7 cells	skin repair	antibacterial activity
	9.3 M LiBr, 60 °C, 30 min		RAW264.7 cells	hair follicle regeneration	antibacterial activity
IEM	0.02 M Na₂CO₃, boiling temperature, 30 min	FPP	murine fibroblast (L-929) cells	can be applied in the microelectronics industry and SF-based microdevices	simplicity of the production	(37)
	9.3 M LiBr			functionalization of nanomaterials through biotemplating or prototyping tools	tuning the mechanical strength and degradation
				biological arrays, tissue engineering, and drug delivery	being biocompatible
				biological arrays, tissue engineering, and drug delivery	formation of the complex structure with precise shape and size
IEM	0.02 M Na₂CO₃, 100 °C, 30 min	FPP	female mouse embryonic fibroblasts (MEFs)	can be used for optics, delivery, or bilocally functional agents	monodisperse and precise shapes	(36)
	9.3 M LiBr			controlled release applications	fully biodegradable
					biocompatible
					controlling degradation with carrying size, thickness, and degree of cross-linking of SF proteins
IEM	0.01 M C₁₈H₃₃NaO₂	SFMA		various biomedical applications, 3D printing ink, injectable hydrogel, cell culture matrix and surgical glue.	good water solubility at various degrees of methacrylation	(35)
	0.02 + 0.02 M Na₂CO₃, 60 min				quick gelation time (<60 s)
	9.3 M LiBr: 0.6 M NaOH, 80 °C				high elasticity compared to physically cross-linked SF
GMA	0.05 M Na₂CO₃, 100 °C, 30 min	silk-GMA	NIH/3T3 cells	cartilage regeneration	capability to be used as bioink	(73)
	9.3 M LiBr, 60 °C, 1 h		human chondrocyte	3D DLP printing	good mechanical strength
	9.3 M LiBr, 60 °C, 1 h		human chondrocyte	3D DLP printing	good biocompatibility
GMA	NM	SF-GMA		scaffold and wound dressing agents	dual cross-linking mechanism can be used	(34)
GMA	CaCl₂/EtOH/H₂O (1:2:8 M ratio), 70 °C, 1 h	SF-GMA		scaffold and wound dressing agents	high stability for cell attachment, migration, and proliferation	(34)
GMA	0.05 M Na₂CO₃, 100 °C, 30 min	SB	Neuro2a cells	digital light processing (DLP) printable bioink	high mechanical strength (>500 kPa)	(28)
GMA	9.3 M LiBr, 60 °C, 1 h	SB	Neuro2a cells	digital light processing (DLP) printable bioink	electroconductivity increased by incorporation of GO in SFMA	(28)
GMA	0.05 M Na₂CO₃, 100 °C, 30 min	Sil-MAS	NIH/3T3 cells	in vitro and in vivo hemostatic and wound healing effects	sealing without any surgical method	(33)
	0.05 M Na₂CO₃, 100 °C, 30 min			laparoscopic tool in field of robotic surgery	excellent adhesive properties with wound closure strength more than 25 kPa
	9.3 M LiBr, 60 °C, 1 h			versatile medical glue for clinical applications	hemostatic effects
					high biocompatibility
					adequate degradation time (25.1% in vitro degradation in 30 days)
GMA	0.02 M Na₂CO₃, 100 °C, 1 h	Sil-MA	primary meniscus cell (pMCs)	an attractive alternative to producing fibrocartilaginous tissues.	excellent structural integrity and biomechanical performance	(27)
GMA	9.3 M LiBr, 70 °C, 1 h	Sil-MA	primary meniscus cell (pMCs)		integrity, with no dimensional changes to fibrocartilaginous tissue	(27)
GMA	0.1 M Na₂CO₃, 100 °C, 30 min	SF-g-GMA		meniscus tissue engineering	effect of the CaCl₂ concentrations and ratio of the SF to the CaCl₂ on SF solubility	(125)
	0.1 M Na₂CO₃, 100 °C, 30 min				effect of the dialysis time on efficiency of the salt removing
	3.6, 4.5, and 5.4 M CaCl₂, 70 °C, 6 h				effect of the SF to GMA molar ratio on grafting process and amounts
GMA	0.05 M Na₂CO₃ 100 °C, 1 h	silk-GMA	NIH/3T3 cells mouse embryonic fibroblast cell line	hydrogel with potential to be applied in clinical transplantation for tissue engineering and biomedical applications	effect of dialysis period on the β-sheet contents of SF and cell proliferation and viability rate (live–dead assays showed 66% and 97% cell viability for hydrogels with 0 and 7 days of dialysis)	(60)
GMA	9.3 M LiBr, 60 °C, 1 h	silk-GMA	NIH/3T3 cells mouse embryonic fibroblast cell line			(60)
GMA	0.02 M Na₂CO₃, 100 °C 30 min	silkMA	human dermal fibroblasts (HDFs)	tissue engineering applications	the effect of the pH on the rheology of the hydrogel, mechanical strength, swelling behavior, cell proliferation and attachments; the SFMA with pH 8 shows more than twice hydrogel expansion (34.4%) and swelling ratio (86%), compared with SFMA with pH 5	(30)
	9.3 M LiBr, 60 °C, 1 h				the compressive modulus of SFMA at pH 5 is twice as high (40 kPa) as SFMA at pH 7
	9.3 M LiBr, 60 °C, 1 h				cell viability of more than 90%
GMA	1st bath: 0.01 M Na₂CO₃ 100 °C, 1 h	SF-MA	NIH 3T3	can be used as biomaterials with extra functionalities	nontoxic	(29)
	2nd bath: 0.001 M Na₂CO₃, 100 °C, 1 h				biocompatible (more than 80% cell viability)
	9.3 M LiBr, 4 h, 65 °C				biocompatible (more than 80% cell viability)
GMA	0.02 M Na₂CO₃, 100 °C, 1 h	Sil-MA	NIH 3T3	Ink to build complex organ structures, including the heart, vessel, brain, trachea and ear	tuning the mechanical strength with varying the SFMA content (compressive stress at break of around 910 kPa for 30% SFMA)	(24)
	0.02 M Na₂CO₃, 100 °C, 1 h		chondrocytes were isolated from human septal cartilage		outstanding mechanical and rheological properties
	9.3 M LiBr, 60 °C, 1 h				excellent structural ability
	9.3 M LiBr, 60 °C, 1 h				reliable biocompatibility
CA	0.03 M C₁₈H₃₃NaO₂	SF-NB	mouse embryonic fibroblasts (NIH/3T3)	three-dimensional cell culture requiring temporal control of hydrogel stiffness	controllable cross-linking based on two mechanisms including thiol–ene and photoclick reaction.	(39)
	0.04 + 0.02 M Na₂CO₃ 60 min			cell encapsulation	elastic moduli of 1.5–3 kPa depend on the SFNB contents (0–4 wt %)
	9.3 M LiBr 60 °C, 1 h		adenocarcinoma human alveolar basal epithelial cells (A549)	tumor development and tissue fibrosis model
CA	0.05 M Na₂CO₃, 100 °C, 40 min	RFS-NB	mouse fibroblast (L929) cells	3D printed scaffolds for tissue engineering	good biocompatibility (>95%)	(40)
CA	9.3 M LiBr, 40 °C, 40 min	RFS-NB	mouse fibroblast (L929) cells	3D printed scaffolds for tissue engineering	mechanical strength depends on the UV exposure time (by increasing the UV exposure time from 1 to 10, the ultimate storage modulus increases from 51 to 1700 Pa)	(40)